Fix changeid links in gerrit

Previously the wrong regex substitution was used in changeid links.
The replacement $1 refers to the first parentheses-enclosed match
where the regex itself didn't have any parentheses. Instead use
the entire match as a substitute in the link.

Change-Id: I7c21bfbb575440396c75cb56a03a0573150ba411
Merge "Fix changeid links in gerrit"