Merge pull request #768 from betheg/as

gradle: fix Cannot set property outputFile on null object.

build.gradle

@@ -84,7 +84,9 @@ android {
 	applicationVariants.all { variant ->
 		if (variant.name.equals('release')) {
 			variant.outputs.each { output ->
+				if (output.zipAlign != null) {
 					output.zipAlign.outputFile = new File(output.outputFile.parent, rootProject.name + "-${variant.versionName}.apk")
+				}
 				output.packageApplication.outputFile = new File(output.outputFile.parent, output.packageApplication.outputFile.name
 					.replace(".apk", "-${variant.versionName}.apk"))
 			}