Weather: Fix Regex Check for Warnings; Fix Bug in Chance of Rain, Remove Unnecessary Print Log

- Made the regex change proposed by @gac410 re: one line warning regex in chance of rain. Fixes issue raised in hollie/misterhouse#357
- Remove extra 'Return' reference in chance of rain.  This was causing the chance of rain loopcode to exit prematurely.  In my case the was preventing the creating of the "read chance of rain" trigger.
- Removed print log entry of 'WEATHER WARNING' It isnt't necessary as the read command will cause a print log entry if necessary