Fix nfs mount completion if the path to showmount contains a space.

contrib/mount

@@ -17,7 +17,7 @@ _mount()
     [[ "$cur" == \\ ]] && cur="/"
 
     if [[ "$cur" == *:* ]]; then
-        for sm in $(type -P showmount) {,/usr}/{,s}bin/showmount; do
+        for sm in "$(type -P showmount)" {,/usr}/{,s}bin/showmount; do
             [ -x "$sm" ] || continue
             COMPREPLY=( $( compgen -W "$( "$sm" -e ${cur%%:*} | \
                 awk 'NR>1 {print $1}' )" -- "${cur#*:}" ) )