It would only show 70 chars.
The commit-message-max-width variable is unused since change 113890, so
let's remove it.
The css rule for larger screens did not have any effect, because the
commit message element would need a flex-grow > 0 for that. I think with
what I have in mind for the future of the change page layout it is good
to keep the width fixed at 72 chars all the time.
Change-Id: I1aabe3566b9e191317f8d2ee8889fda3d8f986f7
(cherry picked from commit 86ebd20800)
54d667b7e6