releasetools: Fix the bug with TARGET_NO_RECOVERY.

The packaging script is broken when we set TARGET_NO_RECOVERY and
SYSTEM_ROOT_IMAGE both. With TARGET_NO_RECOVERY set, we don't have
RECOVERY/RAMDISK/etc/recovery.fstab. It thus fails the assertion in
common.LoadRecoveryFSTab() that "/" must exist in fstab when enabling
SYSTEM_ROOT_IMAGE.

Change-Id: Id509d724f18be7cf7389dd786924ead894ac0cc1
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 872dd4c..2c8bbc6 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -211,8 +211,11 @@
   makeint("boot_size")
   makeint("fstab_version")
 
-  d["fstab"] = LoadRecoveryFSTab(read_helper, d["fstab_version"],
-                                 d.get("system_root_image", False))
+  if d.get("no_recovery", False) == "true":
+    d["fstab"] = None
+  else:
+    d["fstab"] = LoadRecoveryFSTab(read_helper, d["fstab_version"],
+                                   d.get("system_root_image", False))
   d["build.prop"] = LoadBuildProp(read_helper)
   return d