Exclude the bind -x commands from interactive commands (#152)

* Exclude the `bind -x` commands from interactive commands

* Check COMP_POINT instead of possibly empty COMP_LINE

The check for COMP_LINE can fail because it can be empty in the
completion function for the empty command line "complete -F _func -E".

bash-preexec.sh

@@ -222,9 +222,9 @@ __bp_preexec_invoke_exec() {
         return
     fi
 
-    if [[ -n "${COMP_LINE:-}" ]]; then
-        # We're in the middle of a completer. This obviously can't be
-        # an interactively issued command.
+    if [[ -n "${COMP_POINT:-}" || -n "${READLINE_POINT:-}" ]]; then
+        # We're in the middle of a completer or a keybinding set up by "bind
+        # -x".  This obviously can't be an interactively issued command.
         return
     fi
     if [[ -z "${__bp_preexec_interactive_mode:-}" ]]; then