shell: use 'command -v' instead of 'hash' (for non-bash)

see https://stackoverflow.com/a/677212

plugins/network/multibandwidth

@@ -78,7 +78,7 @@ case $1 in
                 done
         exit 0;;
     autoconf)
-                if hash bing 2>/dev/null; then
+                if command -v bing >/dev/null 2>&1; then
                         echo 'yes'
                         exit 0;
                 else