coccinelle: ignore ASTs pre-parsed cached C files

files generated using coccinelle tool: 'spatch --use-cache'
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20170718045540.16322-2-f4bug@amsat.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

.gitignore

@@ -116,6 +116,8 @@ tags
 TAGS
 docker-src.*
 *~
+*.ast_raw
+*.depend_raw
 trace.h
 trace.c
 trace-ust.h