rra-c-util 2.7

I'm releasing a new version of WebAuth, so time to release a new version of rra-c-util as well.

The only code change in this release is an improvement to the krb5.m4 Autoconf macros. It now looks for krb5-config in /usr/kerberos/bin after checking the user's PATH, since versions of Red Hat Enterprise prior to 6 installed krb5-config there instead.

This release also uncomments all the additional probes in configure.ac so that they'll be tested during rra-c-util builds, and fixes one syntax error in the Kerberos v4 probes.

You can get the latest version from the rra-c-util distribution page.