gitignore: Ignore vm test images

Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

.gitignore

@@ -52,6 +52,7 @@
 /vscclient
 /vhost-user-scsi
 /fsdev/virtfs-proxy-helper
+*.tmp
 *.[1-9]
 *.a
 *.aux

tests/.gitignore

@@ -95,3 +95,4 @@ test-filter-mirror
 test-filter-redirector
 *-test
 qapi-schema/*.test.*
+vm/*.img