Use 'double' instead of 'mock' about rspec-mock

'mock' is deprecated after rspec-mock 2.14.0.rc1(2013-05-27 released).
'mock' method may be removed for rspec-mock 3.0.0.

And, this fixes can remove following warnings.
DEPRECATION: mock is deprecated. Use double instead. Called from ...
Use 'stub' instead of 'stub!' about rspec-mock

'stub!' is deprecated after rspec-mock 2.14.0.rc1(2013-05-27 released).
'stub!' method may be removed for rspec-mock 3.0.0.

And, this fixes can remove following warnings.
DEPRECATION: stub! is deprecated. Use stub instead. Called from ...
Merge pull request #203 from co-me/unuse-deprecated-method

Stop using deprecated rspec-mock methods