request-pull: avoid mentioning that the start point is a single commit

Previously we ran shortlog on the start commit which always printed
"(1)" after the start commit, which gives no information, but makes the
output less easy to read.  Instead of giving the author name of the
commit, use the space for committer timestamp to help recipient judge
the freshness of the offered branch more easily.

Signed-off-by: Miklos Vajna <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Miklos Vajna

git-request-pull.sh

@@ -65,11 +65,11 @@ if [ -z "$branch" ]; then
 	status=1
 fi
 
-echo "The following changes since commit $baserev:"
-git shortlog --max-count=1 $baserev | sed -e 's/^\(.\)/  \1/'
+git show -s --format='The following changes since commit %H:
 
-echo "are available in the git repository at:"
-echo
+  %s (%ci)
+
+are available in the git repository at:' $baserev
 echo "  $url $branch"
 echo