Treat /vendor like /system for read only

The vendor partition is verity checked just like system so we
should treat vendor as read only same as system.

Change-Id: Ida65c9f44d8610e52fcdcef0b4a50faf5c7110d2
diff --git a/twrp.cpp b/twrp.cpp
index 50db725..ff7d55f 100644
--- a/twrp.cpp
+++ b/twrp.cpp
@@ -345,6 +345,7 @@
 #ifndef TW_OEM_BUILD
 	// Check if system has never been changed
 	TWPartition* sys = PartitionManager.Find_Partition_By_Path("/system");
+	TWPartition* ven = PartitionManager.Find_Partition_By_Path("/vendor");
 	if (sys) {
 		if ((DataManager::GetIntValue("tw_mount_system_ro") == 0 && sys->Check_Lifetime_Writes() == 0) || DataManager::GetIntValue("tw_mount_system_ro") == 2) {
 			if (DataManager::GetIntValue("tw_never_show_system_ro_page") == 0) {
@@ -354,11 +355,15 @@
 				}
 			} else if (DataManager::GetIntValue("tw_mount_system_ro") == 0) {
 				sys->Change_Mount_Read_Only(false);
+				if (ven)
+					ven->Change_Mount_Read_Only(false);
 			}
 		} else if (DataManager::GetIntValue("tw_mount_system_ro") == 1) {
 			// Do nothing, user selected to leave system read only
 		} else {
 			sys->Change_Mount_Read_Only(false);
+			if (ven)
+				ven->Change_Mount_Read_Only(false);
 		}
 	}
 #endif