conditionally define Ruby 1.8.7 patch

Author: JonRowe

lib/rspec/core/shared_example_group.rb

@@ -240,8 +240,14 @@ def warn_if_key_taken(context, key, new_block)
           end
         end
 
-        def formatted_location(block)
-          block.source_location.join(":").gsub(/:in.*$/, '')
+        if RUBY_VERSION.to_f >= 1.9
+          def formatted_location(block)
+            block.source_location.join(":")
+          end
+        else # 1.8.7
+          def formatted_location(block)
+            block.source_location.join(":").gsub(/:in.*$/, '')
+          end
         end
 
         if Proc.method_defined?(:source_location)