completion: cleanup zsh wrapper

There's no need for a separate function; we can call
'emulate -k ksh func'.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Felipe Contreras

contrib/completion/git-completion.bash

@@ -2689,21 +2689,13 @@ if [[ -n ${ZSH_VERSION-} ]]; then
 		compadd -Q -p "${2-}" -f -- ${=1} && _ret=0
 	}
 
-	__git_zsh_helper ()
-	{
-		emulate -L ksh
-		local cur cword prev
-		cur=${words[CURRENT-1]}
-		prev=${words[CURRENT-2]}
-		let cword=CURRENT-1
-		__${service}_main
-	}
-
 	_git ()
 	{
-		emulate -L zsh
-		local _ret=1
-		__git_zsh_helper
+		local _ret=1 cur cword prev
+		cur=${words[CURRENT]}
+		prev=${words[CURRENT-1]}
+		let cword=CURRENT-1
+		emulate ksh -c __${service}_main
 		let _ret && _default -S '' && _ret=0
 		return _ret
 	}