Revert "Allow system images larger than 2GiB."

This reverts commit cd082d4bfe917b2e6b97436839cbbbc67c733c83.

Change-Id: Ie63e1ba70d907d2849164871bc7ec71c245f7af9
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 6517bf3..945f11a 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -646,8 +646,10 @@
   WriteMetadata(metadata, output_zip)
 
 
-def WritePolicyConfig(file_name, output_zip):
-  common.ZipWrite(output_zip, file_name, os.path.basename(file_name))
+def WritePolicyConfig(file_context, output_zip):
+  f = open(file_context, 'r');
+  basename = os.path.basename(file_context)
+  common.ZipWriteStr(output_zip, basename, f.read())
 
 
 def WriteMetadata(metadata, output_zip):