gnupg-with-gpgkey: allow running on Ubuntu

In Git for Windows, we explicitly forbit Git from passing the
`--status-fd=2` option to GPG. But on Ubuntu, that option is passed, and
it is rather crucial because Git reads the status from `stderr` and is a
bit miffed if it does not get any status update there. The symptom is:

	error: gpg failed to sign the data
	error: unable to sign the tag

Let's prepare the script to allow for that option to be passed (and also
allow for that option _not_ to be passed).

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

gnupg-with-gpgkey.sh

@@ -9,8 +9,19 @@
 # using secret variables, of course).
 
 case "$1" in
+--status-fd=*)
+	status_fd="$1"
+	arg1="$2"
+	;;
+*)
+	status_fd=
+	arg1="$1"
+	;;
+esac
+
+case "$arg1" in
 -bsau)
-	eval gpg --batch --yes --no-tty --pinentry-mode loopback -bsau $GPGKEY
+	eval gpg --batch --yes --no-tty --pinentry-mode loopback $status_fd -bsau $GPGKEY
 	;;
 --detach-sign)
 	case "$*" in