P0409R2 - allow lambda capture [=, this]
	* parser.c (cp_parser_lambda_introducer): For cxx2a don't pedwarn on
	redundant [=, this].

	* g++.dg/cpp1z/lambda-this1.C: Don't expect error for c++2a on [=, this]
	capture.  Add further tests.
	* g++.dg/cpp0x/lambda/lambda-capture-redundancy.C: Don't expect error
	for c++2a on [=, this] capture.

From-SVN: r253030