Default to git_installed

Author: justin808

lib/react_on_rails/git_utils.rb

@@ -4,7 +4,7 @@
 
 module ReactOnRails
   module GitUtils
-    def self.uncommitted_changes?(message_handler, git_installed = $CHILD_STATUS.success?)
+    def self.uncommitted_changes?(message_handler, git_installed = true)
       return false if ENV["COVERAGE"] == "true"
 
       status = `git status --porcelain`