libcutils: fix rw FS remount check issue

In some condition, some of FS would set disable_roll_forward option.
In this case, when we do power off or reboot, the power down progress
would stuck at android_reboot for 360 sec.
The reason is, remount_ro_done function check key word "rw" to determine
whether all the read-write FS has been remounted as read-only FS.
Unfortunately, it takes disable_roll_forward as a rw flag too by
mistake, so the check would always fail, until reach 360 sec threshold.

The patch would match "rw," from mount options, this can avoid the issue
successfully.

Change-Id: I409f9dc88c9ee5cf049615ea9dcccaf195b6bc5a
Signed-off-by: Hong-Mei Li <a21834@motorola.com>
diff --git a/libcutils/android_reboot.c b/libcutils/android_reboot.c
index b7895fa..5d98295 100644
--- a/libcutils/android_reboot.c
+++ b/libcutils/android_reboot.c
@@ -57,7 +57,7 @@
         mount_dir[255] = 0;
         mount_type[255] = 0;
         mount_opts[255] = 0;
-        if ((match == 6) && !strncmp(mount_dev, "/dev/block", 10) && strstr(mount_opts, "rw")) {
+        if ((match == 6) && !strncmp(mount_dev, "/dev/block", 10) && strstr(mount_opts, "rw,")) {
             found_rw_fs = 1;
             break;
         }