This reverts commit 83ecce54.

Conflicts:
	src/lib/python/isc/bind10/socket_cache.py

Conflicts:
	src/lib/python/isc/bind10/socket_cache.py

Conflicts:
	src/bin/bind10/bind10_src.py.in
	src/bin/bind10/tests/bind10_test.py.in

Conflicts:
	ChangeLog
	src/bin/auth/statistics.cc
	src/bin/auth/statistics.h
	src/lib/Makefile.am

also be more strict of 'target': we don't (yet) support non NULL case for it
in this Python version anyway, so it must be None.  Added a check for it.
docstring was also updated accordingly.

Just a naming convention

rename addWildcardNxrrsetProof to addWildcardNXRRSETProof
(for consistency with addNXDOMAINProof())

Conflicts:
	ChangeLog

ticket #510.