Objective-C++ : Address a FIXME.

Objective-C++ : Address a FIXME.

We can avoid the spurious additional complaint about a closing
')' by short-circuiting the test in the case we know there's a
syntax error already reported.

gcc/cp/ChangeLog:

	* parser.c (cp_parser_objc_at_property_declaration): Use any
	exisiting syntax error to suppress complaints about a missing
	closing parenthesis in parsing property attributes.

gcc/testsuite/ChangeLog:

	* obj-c++.dg/property/at-property-1.mm: Adjust test after
	fixing spurious error output.