Set system-partition mount point to proper location

This sets the system mount point to either /system_root or /system
depending on whether SAR is detected or not irregardless of what
is specified in fstab.

This removes the need to edit fstab for SAR-builds and simplifies
building unified (SAR/non-SAR) builds.

Change-Id: I154fd76f842702be9e5d09005463c8e5f1d289a4
diff --git a/partition.cpp b/partition.cpp
index beb4a81..9012d49 100644
--- a/partition.cpp
+++ b/partition.cpp
@@ -436,7 +436,10 @@
 	} else if (Is_File_System(Fstab_File_System)) {
 		Find_Actual_Block_Device();
 		Setup_File_System(Display_Error);
-		if (Mount_Point == PartitionManager.Get_Android_Root_Path()) {
+		if (Mount_Point == "/" || Mount_Point == "/system" || Mount_Point == "/system_root") {
+			Mount_Point = PartitionManager.Get_Android_Root_Path();
+			Backup_Path = Mount_Point;
+			Storage_Path = Mount_Point;
 			Display_Name = "System";
 			Backup_Display_Name = Display_Name;
 			Storage_Name = Display_Name;