Remove static const char copyright[]

We do not have copyright strings in our other executables for the other
copyright statements applicable to them, so these are rather exceptional.
They also cause build failures with OS X Xcode 5.1 and --enable-checking .

Change-Id: I0ead56387f77459a49093ff66fdea9c033f02f5a
Reviewed-on: http://gerrit.openafs.org/10888
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>