merge revision(s) 42100: [Backport #8806]

	* ext/date/date_parse.c (rfc2822_cb): check if wday is given, since it
	  can be omitted.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@42774 b2dd03c8-39d4-4d8f-98ff-823fe69b080e