Drop check for NTE_BAD_KEYSET error

Any error when acquiring the CryptoAPI context should get treated as
bad.  Also, this one can't happen for the arguments we're giving.
Fixes bug 10816; bugfix on 0.0.2pre26.
Stop using default authorities with both Alternate Dir and Bridge Authority

Stop using the default authorities in networks which provide both
AlternateDirAuthority and AlternateBridgeAuthority.

This bug occurred due to an ambiguity around the use of NO_DIRINFO.
(Does it mean "any" or "none"?)

Partially fixes bug 13163.
Improve DIRINFO flags' usage comments

Document usage of the NO_DIRINFO and ALL_DIRINFO flags clearly in functions
which take them as arguments. Replace 0 with NO_DIRINFO in a function call
for clarity.

Seeks to prevent future issues like 13163.
Bitwise check BRIDGE_DIRINFO

Bitwise check for the BRIDGE_DIRINFO flag, rather than checking for
equality.

Fixes a (potential) bug where directories offering BRIDGE_DIRINFO,
and some other flag (i.e. microdescriptors or extrainfo),
would be ignored when looking for bridge directories.

Final fix in series for bug 13163.
Merge remote-tracking branch 'teor/bug-13163-AlternateAuthorities-type-handling-fixed'
Merge remote-tracking branch 'public/bug10816'