Ruby » Ruby master

• lib/rubygems/dependency_installer.rb: Only install local gems if
  they end in '.gem'. Fixes github rubygems issue #407.
• test/rubygems/test_gem_dependency_installer.rb: Test for the above.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39139 b2dd03c8-39d4-4d8f-98ff-823fe69b080e