[chirp_devel] FIx for #5599

Attached is the new driver for Radio Shack PRO-649 scanner. Issue #5599 The Clone test will report Failed, since I trap a radio download timeout and generate an empty memory set. The radios were sold with a USB dongle that does not handshake the download dump. There may be a future patch to fix this if I ever find a dongle that works. Meanwhile it is a "write-only" device. This is explained in the download prompts.