Merge branch 'ma/bash-completion-leaking-x' into maint

The completion script (in contrib/) contaminated global namespace
and clobbered on a shell variable $x.

* ma/bash-completion-leaking-x:
  completion: fix global bash variable leak on __gitcompappend

contrib/completion/git-completion.bash

@@ -186,7 +186,7 @@ fi
 
 __gitcompappend ()
 {
-	local i=${#COMPREPLY[@]}
+	local x i=${#COMPREPLY[@]}
 	for x in $1; do
 		if [[ "$x" == "$3"* ]]; then
 			COMPREPLY[i++]="$2$x$4"