fs_mgr: Allow remounts with Magisk installed

This allows remount to gracefully mount /system when Magisk
is installed.

As a sidenote, the ro.debuggable property check can safely
be removed due to the simple fact that CPP preprocessor flag
ALLOW_ADBD_DISABLE_VERITY=1 is passed when building
userdebug/eng.

Change-Id: Ic10eccbf5d225468c3dc42f8ae3ae7c05b49a699

fs_mgr/fs_mgr_remount.cpp

@@ -625,7 +625,7 @@ int main(int argc, char* argv[]) {
     // If somehow this executable is delivered on a "user" build, it can
     // not function, so providing a clear message to the caller rather than
     // letting if fall through and provide a lot of confusing failure messages.
-    if (!ALLOW_ADBD_DISABLE_VERITY || !android::base::GetBoolProperty("ro.debuggable", false)) {
+    if (!ALLOW_ADBD_DISABLE_VERITY) {
         LOG(ERROR) << "Device must be userdebug build";
         return EXIT_FAILURE;
     }