Insteon: Remove Unnecessary Test of Data3 Inside Has_Link Routine

The linkkey contains the data3 value.  If the linkkey matches there is no need to check the data3 value.

For the PLM data3 is currently ignored because MH sets data3 on responder links to 00, while manually linking sets it to the device's firmware.
Insteon: Clear Array of Sync Failures When Starting a New Sync
Insteon: Clear Delete Failure Array When Starting Delete Orphans
Merge pull request #371 from krkeegan/fix_insteon_has_link

Insteon: Clear Failure List on Sync/Delete All; Fix Discrepancy with Data3