Add in acloud.sh to be main entry point into acloud.

Bug: None
Test: acloud.sh kicks off acloud.
Change-Id: I87b08704100ad79f7bace0ea5a87b584bd34b29c
diff --git a/public/acloud_main.py b/public/acloud_main.py
index 49894fe..403a0af 100644
--- a/public/acloud_main.py
+++ b/public/acloud_main.py
@@ -106,7 +106,7 @@
     parser = argparse.ArgumentParser(
         description=__doc__,
         formatter_class=argparse.RawDescriptionHelpFormatter,
-        usage="%(prog)s {" + usage + "} ...")
+        usage="acloud {" + usage + "} ...")
     subparsers = parser.add_subparsers()
     subparser_list = []