Accomodate to the import syntax in build.prop.

Bug: 14024566
Change-Id: I70b8d3c8cfc968a7f039728375f3f7f341cdc11a
diff --git a/tools/post_process_props.py b/tools/post_process_props.py
index a971683..e43ca59 100755
--- a/tools/post_process_props.py
+++ b/tools/post_process_props.py
@@ -85,8 +85,9 @@
     for line in self.lines:
       if not line or line.startswith("#"):
         continue
-      key, value = line.split("=", 1)
-      props[key] = value
+      if "=" in line:
+        key, value = line.split("=", 1)
+        props[key] = value
     return props
 
   def get(self, name):