Harmonize link text in ITS comments

While the link text in ITS comments for gerrit comments started in
  Gerrit Change [Change-Id]
(without colon), the link text in ITS comments for added patch sets
started in
  Gerrit Patch-Set: [Change-Id]/[Patch Set-Id]
(with colon). We now harmonize those messages and drop the colon.

Change-Id: I535c1186a469e746a65bd7024c0f5c65cedd49b7