tree-cfg.c (move_stmt_op): Reset the expr block only when necessary.

2012-09-24  Dehao Chen  <dehao@google.com>

	* tree-cfg.c (move_stmt_op): Reset the expr block only
	when necessary.
	(move_block_to_fn): Reset the edge's goto block even
	when the goto locus is unknown.

From-SVN: r191680