Revert "Ignore errors when BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH is not defined in .config."

This reverts commit 8a9a98c.

Author: albertd

board/raspberrypi/post-build.sh

@@ -8,7 +8,7 @@ persistent_path="/root"
 echo "Post-build: processing $@"
 
 # Look for persistent path variable in .config
-BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH="$(grep ^BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH= ${BR2_CONFIG})" || true
+BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH="$(grep ^BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH= ${BR2_CONFIG})"
 
 if [[ $BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH == BR2_PACKAGE_WPEFRAMEWORK_PERSISTENT_PATH=* ]]; 
 then