tools: add shared current directory handle helper

Add tool_current_dhandle_only() as a small wrapper for callers that only need
the current NetWare directory handle.

Replace the local creator_current_dhandle() and tests_current_dhandle()
implementations in CREATOR and NWTESTS with the shared helper. This removes
duplicate requester-current-directory code without changing behavior.

tools.c

@@ -596,6 +596,13 @@ int tool_current_dhandle(uint8 *connid, uint8 *dhandle)
   return(0);
 }
 
+int tool_current_dhandle_only(uint8 *dhandle)
+{
+  uint8 connid = 0;
+
+  return(tool_current_dhandle(&connid, dhandle));
+}
+
 int tool_current_prefix(char *out, int max)
 {
   uint8 connid = 0;