fix(__load_completion): check _comp_realcommand return code

Author: scop

bash_completion

@@ -2525,8 +2525,7 @@ __load_completion()
 
     # 3) From bin directories extracted from $(realpath "$cmd") and PATH
     local ret
-    _comp_realcommand "$1"
-    paths=("${ret%/*}")
+    _comp_realcommand "$1" && paths=("${ret%/*}") || paths=()
     _comp_split -aF : paths "$PATH"
     for dir in "${paths[@]%/}"; do
         if [[ -d $dir && $dir == ?*/@(bin|sbin) ]]; then