git: use rev-list for fetching last commit data inc ase of single commit. It's faster that using git log

rhodecode/lib/vcs/backends/git/commit.py

@@ -309,6 +309,10 b' class GitCommit(base.BaseCommit):'
         self._get_filectx(path)
         f_path = safe_str(path)
 
+        # optimize for n==1, rev-list is much faster for that use-case
+        if limit == 1:
+            cmd = ['rev-list', '-1', self.raw_id, '--', f_path]
+        else:
         cmd = ['log']
         if limit:
             cmd.extend(['-n', str(safe_int(limit, 0))])