perf(__load_completion): avoid a subshell on completion install check

#924 (comment)

Co-authored-by: Koichi Murase <[email protected]>

Author: scop

bash_completion

@@ -2592,7 +2592,7 @@ __load_completion()
                         return 0
                     fi
                     # If not, see if we got one for $cmdname
-                    if compspec=$(complete -p "$cmdname" 2>/dev/null); then
+                    if [[ $cmdname != "$cmd" ]] && compspec=$(complete -p "$cmdname" 2>/dev/null); then
                         # Use that for $cmd too, if we have a full path to it
                         [[ $cmd == /* ]] && $compspec "$cmd"
                         return 0