Don't add CA certs to the chain

We spotted this with a local build of the VOMS library that included lots of debugging information. Here's an example of a failing run:

Jul 14 17:45:25 gridppcl02 python: Entering VOMS_Retrieve...
Jul 14 17:45:25 gridppcl02 python: Entering vomsdata::Retrieve(3)...
Jul 14 17:45:25 gridppcl02 python: Entering vomsdata::retrieve(7)...
Jul 14 17:45:25 gridppcl02 python: Leaving vomsdata::retrieve(7) (found with no recursion)...
Jul 14 17:45:25 gridppcl02 python: There are no other lines that say this.
Jul 14 17:45:25 gridppcl02 python: vomsdata::Retrieve(3): Attempting evaluate...
Jul 14 17:45:25 gridppcl02 python: Entering vomsdata::evaluate(4)...
Jul 14 17:45:25 gridppcl02 python: Entering vomsdata::verifydata(4)...
Jul 14 17:45:25 gridppcl02 python: Entering vomsdata::verifyac(5)...
Jul 14 17:45:25 gridppcl02 python: Entering validate...
Jul 14 17:45:25 gridppcl02 python: Passed validate 'valids'...
Jul 14 17:45:25 gridppcl02 python: Passed validate 'sign'...
Jul 14 17:45:25 gridppcl02 python: Passed validate 'some more CA stuff'...
Jul 14 17:45:25 gridppcl02 python: Validate, verifying ID...
Jul 14 17:45:25 gridppcl02 python: Validate, Doing holder baseid branch...
Jul 14 17:45:25 gridppcl02 python: Holder serials (39217, 256)
Jul 14 17:45:25 gridppcl02 python: Holder serial error! (39217 != 256)
Jul 14 17:45:25 gridppcl02 python: Validate, Checked serial & issuer...
Jul 14 17:45:25 gridppcl02 python: Leaving vomsdata::verifyac(5)... (Result: 5030)
Jul 14 17:45:25 gridppcl02 python: Leaving vomsdata::verifydata(4)... Other Cannot verify AC signature!
Jul 14 17:45:25 gridppcl02 python: Leaving vomsdata::evaluate(4)... (OK = 0)
Jul 14 17:45:25 gridppcl02 python: Leaving vomsdata::Retrieve(3)...
Jul 14 17:45:25 gridppcl02 python: Leaving VOMS_Retrieve (Code: 17)...

Note that the serial check fails. 256 is the code for a CA cert, which is why we kept seeing that number.

Here's the output after we applied the change:

Jul 14 17:47:28 gridppcl02 httpd: Entering VOMS_Retrieve...
Jul 14 17:47:28 gridppcl02 httpd: Entering vomsdata::Retrieve(3)...
Jul 14 17:47:28 gridppcl02 httpd: Entering vomsdata::retrieve(7)...
Jul 14 17:47:28 gridppcl02 httpd: Leaving vomsdata::retrieve(7) (found with no recursion)...
Jul 14 17:47:28 gridppcl02 httpd: There are no other lines that say this.
Jul 14 17:47:28 gridppcl02 httpd: vomsdata::Retrieve(3): Attempting evaluate...
Jul 14 17:47:28 gridppcl02 httpd: Entering vomsdata::evaluate(4)...
Jul 14 17:47:28 gridppcl02 httpd: Entering vomsdata::verifydata(4)...
Jul 14 17:47:28 gridppcl02 httpd: Entering vomsdata::verifyac(5)...
Jul 14 17:47:28 gridppcl02 httpd: Entering validate...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'valids'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'sign'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'some more CA stuff'...
Jul 14 17:47:28 gridppcl02 httpd: Validate, verifying ID...
Jul 14 17:47:28 gridppcl02 httpd: Validate, Doing holder baseid branch...
Jul 14 17:47:28 gridppcl02 httpd: Holder serials (39217, 39217)
Jul 14 17:47:28 gridppcl02 httpd: Validate, Checked serial & issuer...
Jul 14 17:47:28 gridppcl02 httpd: Validate, Checked holder...
Jul 14 17:47:28 gridppcl02 httpd: Validate, Checked UID1...
Jul 14 17:47:28 gridppcl02 httpd: Validate, Checked UID2...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'mid 2nd-valid'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'second valids'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'date time checks'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'check extensions'...
Jul 14 17:47:28 gridppcl02 httpd: Passed validate 'check attributes'...
Jul 14 17:47:28 gridppcl02 httpd: Leaving validate... (Result: 0)
Jul 14 17:47:28 gridppcl02 httpd: Leaving vomsdata::verifyac(5)... (Result: 0)
Jul 14 17:47:28 gridppcl02 httpd: Leaving vomsdata::evaluate(4)... (OK = 1)
Jul 14 17:47:28 gridppcl02 httpd: Leaving vomsdata::Retrieve(3)...