Remove 1.9 hash syntax

Author: Michael Bleigh

lib/grape/api.rb

@@ -107,7 +107,7 @@ def version(*args, &block)
 
       # Add a description to the next namespace or function.
       def desc(description, options = {})
-        @last_description = options.merge({description: description})
+        @last_description = options.merge(:description => description)
       end
 
       # Specify the default format for the API's