(fix) move the prevent lines before the curl command

bricks/example.brick

@@ -23,11 +23,11 @@ pkgs() {
 }
 
 install() {
-	sh -c "$(curl https://example.com/script.sh)"
 	# these 2 lines are to prevent it from being installed
 	errcho '`example` brick is not an installable brick, its for packaging reference only'
 	exit 1
 
+	sh -c "$(curl https://example.com/script.sh)"
 }
 
 uninstall() {