testsuite_flags.in (cxxflags): Remove @CXXFLAGS@ since libstdc++.exp imports those flags via getenv.

2014-05-20  Cesar Philippidis  <cesar@codesourcery.com>

	libstdc++-v3/
	* scripts/testsuite_flags.in (cxxflags): Remove @CXXFLAGS@ since 
	libstdc++.exp imports those flags via getenv.
	* testsuite/lib/libstdc++.exp (libstdc++_init): Ensure that 
	CXXFLAGS contains a '-O' flag.

From-SVN: r210659