falcon: init: Look for metadata block to detect GPE variant

This partition is only available for the GPE variant. Look for that
rather then executing blkid.

Change-Id: Ib75322cacaa1d209b732d896269a3fdfadd287fc

init/init_falcon.cpp

@@ -95,10 +95,7 @@ void init_msm_properties(unsigned long msm_id, unsigned long msm_ver, char *boar
 
     property_set("ro.product.model", "Moto G");
     if (ISMATCH(radio, "0x1")) {
-        FILE *fp = popen("/system/bin/blkid /dev/block/platform/msm_sdcc.1/by-name/userdata | /system/bin/cut -d'\"' -f4", "r");
-        fgets(fstype, sizeof(fstype), fp);
-        pclose(fp);
-        if (ISMATCH(fstype, "ext4")) {
+        if (access("/dev/block/platform/msm_sdcc.1/by-name/metadata", F_OK) != -1) {
             /* xt1032 GPE */
             property_set("ro.product.device", "falcon_gpe");
             property_set("ro.build.description", "falcon_gpe-user 5.1 LMY47M.M005 10 release-keys");