merge revision(s) 44861,44862: [Backport #9493]

	* gc.c (get_envparam_int): don't accept a value equals to lowerbound
	  (changed by last commit) because "" or "foo" (not a number) strings
	  are parsed as 0. They should be rejected.

	* gc.c (get_envparam_double): ditto.

	* gc.c (get_envparam_int): accept a value equals to lowerbound.

	* gc.c (get_envparam_int): correct warning messsages.

	* gc.c (get_envparam_double): ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@44868 b2dd03c8-39d4-4d8f-98ff-823fe69b080e