Try /usr/sbin before /sbin in have().

The former tends to have more executables so this should save some
stat() calls in some setups.

bash_completion

@@ -171,7 +171,7 @@ have()
     unset -v have
     # Completions for system administrator commands are installed as well in
     # case completion is attempted via `sudo command ...'.
-    PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin type $1 &>/dev/null &&
+    PATH=$PATH:/usr/sbin:/sbin:/usr/local/sbin type $1 &>/dev/null &&
     have="yes"
 }