rails/rails — pull request #15005 by pan (2014-05-07 05:53:32+00:00)
Title: Fix the warning while building an engine gemspec

After a new plugin is created, if you try to build it with the default generated engine gemspec, the gem(2.2.2) will warn you like this,

```shell
$ gem build engine.gemspec
WARNING: pessimistic dependency on rails (~> 4.1.0) may be overly strict
if rails is semantically versioned, use:
add_runtime_dependency 'rails', '~> 4.1', '>= 4.1.0'
WARNING: open-ended dependency on sqlite3 (>= 0, development) is not recommended
if sqlite3 is semantically versioned, use:
add_development_dependency 'sqlite3', '~> 0'
WARNING: See http://guides.rubygems.org/specification-reference/ for help
```
This fix makes the default engine gemspec follow the recommended
semantical version string for dependency to avoid warnings.