Loosen up modem regexp in cromo init : cherry-pick 5a9d29fe3a6c3ae51c6172e66b02e3836babee2d

We are seeing device names of 1-6.3 instead of 1-6 when we look at the
udev device for our driver.  Make the regexp for validating pathnames
more liberal to accept this.  We still don't accept /, so this should
be security-neutral

BUG=15487
TEST=network_3GRecoverFromGobiDesync + manually add a bogus device to /var/run/cromo/usb-devices and check for debug output

Original Reviewed-on: http://gerrit.chromium.org/gerrit/1209
Original Change-Id: I17059280902ae84fb2cdf4e2ee67cee30a87e208

Change-Id: Ic1e90178d5c351481122d05dba5e7ba12e91225b
Reviewed-on: http://gerrit.chromium.org/gerrit/1249
Tested-by: David Rochberg <rochberg@chromium.org>
Tested-by: Jason Glasgow <jglasgow@chromium.org>
Reviewed-by: Jason Glasgow <jglasgow@chromium.org>
diff --git a/cromo.conf b/cromo.conf
index fcd4c15..38d0651 100644
--- a/cromo.conf
+++ b/cromo.conf
@@ -28,8 +28,9 @@
 #
 post-stop script
 	for dev in $(cat /var/run/cromo/usb-devices); do
-		VALID='^[[:digit:]]\+-[[:digit:]]\+$'
+		VALID='^[[:digit:].:-]\+$'
 		if ! echo "$dev" | grep -q "$VALID" ; then
+            logger -t "upstart-cromo" "Skipping invalid device $dev"
 			continue
 		fi
 		logger -t "upstart-cromo" "rebooting: $dev"