remote-hg: strip extra newline

There's no functional change since mercurial commit operation strips
that anyway, but that's no excuse for us not to do the right thing. So
let's be explicit about it.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Felipe Contreras

contrib/remote-helpers/git-remote-hg

@@ -652,6 +652,10 @@ def parse_commit(parser):
         if parser.check('merge'):
             die('octopus merges are not supported yet')
 
+    # fast-export adds an extra newline
+    if data[-1] == '\n':
+        data = data[:-1]
+
     files = {}
 
     for line in parser: