Set LC_MESSAGES to "C" in tests which run commands.

https://github.com/krb5/krb5/commit/9fb1be9f87e93a9dbd20fce3c9f6aaf1ca3405d2
Commit By: ghudson
Revision: 24964
Changed Files:
U   trunk/src/kadmin/testing/scripts/env-setup.shin
U   trunk/src/tests/dejagnu/config/default.exp
U   trunk/src/util/k5test.py