Remove board import. It isn't used.

tannewt · tannewt · commit 0e8fc0d8ed75 · 2020-01-21T10:43:57.000-08:00
diff --git a/adafruit_ble/__init__.py b/adafruit_ble/__init__.py
@@ -33,7 +33,6 @@
         "This release is not compatible with CircuitPython 4.x; use library release 1.x.x")
 #pylint: enable=wrong-import-position
 
-import board
 import _bleio
 
 from .services import Service
