[Spec] Fix description of a spec

spec/unit/generator/xcconfig/xcconfig_helper_spec.rb

@@ -140,7 +140,7 @@ module Pod
             hash_config['FRAMEWORK_SEARCH_PATHS'].should == '"$(PODS_ROOT)/Parse"'
           end
 
-          it "doesn't ovverides exiting linker flags" do
+          it "doesn't overides exiting linker flags" do
             framework_path = config.sandbox.root + 'Parse/Parse.framework'
             xcconfig = Xcodeproj::Config.new('OTHER_LDFLAGS' => '-framework CoreAnimation')
             @sut.add_framework_build_settings(framework_path, xcconfig, config.sandbox.root)