FAM: Get full traceback when event handling errors
POSIX: Properly stringify ACLs with no user/group specified

This is just a workaround to avoid a traceback; the real fix will
involve making the POSIX tool properly handle ACLs with no user/group
given, which refer to the current user/group of the file they apply
to.
Don't parse unicode XML with encoding

Fix another place where a unicode XML string with an encoding
declaration may be read.  Cf. 0f8d403d1a86cfbfe8222662dc445e16e8f7eff9
added missing docstring
misc/bcfg2.spec: Fix BuildRequires for RHEL7

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>