update swarm v1.2.1-rc1

Signed-off-by: Dong Chen <[email protected]>

library/swarm

@@ -11,4 +11,5 @@
 1.1.2: git://github.com/docker/swarm-library-image@5f284e33ef90b7bc30684ad09a5261c037fc9d5e
 1.1.3: git://github.com/docker/swarm-library-image@4d298d3113a4ecefa83a3f9e18f4aaf4f95f007e
 1.2.0: git://github.com/docker/swarm-library-image@0a35988bfcb18ed0aeb646b511e43e78bc940d07
+1.2.1-rc1: git://github.com/docker/swarm-library-image@603882509bdf37a22a3dada3360a5fc0cfe8490b
 latest: git://github.com/docker/swarm-library-image@0a35988bfcb18ed0aeb646b511e43e78bc940d07