git-push: send "To <remoteurl>" messages to the standard output in --porcelain mode

git-push: send "To <remoteurl>" messages to the standard output in --porcelain mode

git-push prints the line "To <remoteurl>" before above each of the ref status
lines.  In --porcelain mode, these "To <remoteurl>" lines go to the standard
error, but the ref status lines go to the standard output.  This makes it
difficult for the process reading standard output to know which ref status lines
correspond to which remote.  This patch sends the "To <remoteurl>" lines to the
the standard output instead.

Signed-off-by: Larry D'Anna <larry@elder-gods.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>