build: remove -j4 to build contrib

-j option is forbbiden to build contributions.
It may cause link error.

Change-Id: I161032a85450a34c2d4be121df376bfe7ab290e3

compile-ios.sh

@@ -98,7 +98,7 @@ do
 
 	echo "Building contrib"
     make fetch
-	make -j4 || exit 1
+	make || exit 1
 
 	cd ../..
 	echo "Building daemon"