merge revision(s) r45637: [Backport #9726]

	* parse.y (primary): flush cmdarg flags inside left-paren in a
	  command argument, to allow parenthesed do-block as an argument
	  without arguments parentheses.  [ruby-core:61950] [Bug #9726]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@45929 b2dd03c8-39d4-4d8f-98ff-823fe69b080e