[REG 4.15 -> 5.0] Creator uses cherry-pick -x when picking from Gerrit

1. Have a clone of Qt Creator's repository with Gerrit configured as remote.
2. In Creator, open a file from this repository.
3. Select "Tools" -> "Git" -> "Remote Repository" -> "Gerrit..." from the menu.
4. Select a change in Creator's repository and click "Cherry Pick".
5. Check Creator's "Version Control" view.
   You can read something like:

   10:49:46 Running in /home/qtrob/dev/src/creator-5.0: git cherry-pick -x FETCH_HEAD
   [5.0 94438ceffc] QmlJSTools: Guard against null pointer access
    Date: Tue Jul 6 14:04:33 2021 +0200
    1 file changed, 1 insertion(+), 1 deletion(-)
   The command "git cherry-pick -x FETCH_HEAD" finished successfully.
   

"cherry-pick -x" adds a line to the commit message referring to the initial id of the picking change, e.g.:

(cherry picked from commit c14158e3d3138cf6d4cd43d4f459d39bbaeadf81)

In this case, this is wrong because it refers to a change in a temporary branch.

It worked correctly in Creator 4.15.