merge revision(s) 39637,40900: [Backport #8440]

	load.c: reorder conditions

	* load.c (loaded_feature_path): reorder conditions so simple
  comparision comes first.
	* load.c (loaded_feature_path): fix invalid read by index underflow.
	  the beginning of name is also a boundary as well as just after '/'.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@41065 b2dd03c8-39d4-4d8f-98ff-823fe69b080e