build watcher images

Closes-bug: #1952944

Change-Id: I9d2dd025b2a4805ef1755ebbf10f15018d05f1c7
(cherry picked from commit 705fb74)

Author: Marcin Juszkiewicz

kolla/image/build.py

@@ -100,7 +100,6 @@ class Status(Enum):
     },
 
     'source': {
-        "watcher-base",  # https://bugs.launchpad.net/watcher/+bug/1952944
     },
 
     'centos': {