Rename libcom_err to libafscom_err

Rename libcom_err to libafscom_err

We no longer provide a compatible libcom_err, and in fact
we renamed the symbols in our libcom_err several years ago
to reflect this fact.
When we build on a system where KRB5_LIBS includes
-lkrb5 -lcom_err , the new Unix build system will pick up
our libcom_err (as $(AFS_LDFLAGS) is the first argument in
AFS_LDRULE and pulls in a linker search path for our libcom_err)
which does not provide all the needed symbols for libkrb5.

Fully rename our libcom_err away to avoid these conflicts.

FIXES 128640

Change-Id: Ifdd677609f432d42252b1716fc5e8755f3a44640
Reviewed-on: http://gerrit.openafs.org/3547
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>