[gssproxy] [PATCHES] Better logging for basic errors and tests fixes

[Simo Sorce]

One of the most frequent issues with gss-proxy is that of acquiring
credentials when interposing client processes.

The attached patchset adds proper logging (to syslog or journal) when
GSS-Proxy fails to acquire credentials. Hopefully it won't be too
spammy.

Also find attached a set of patches to fix the test framework which
was not actually testing the GSS-Proxy daemon (oops :-)

Simo.