Removes duplicate call to utcoffset() in instance()

Author: sdispater

pendulum/pendulum.py

@@ -221,8 +221,6 @@ def instance(cls, dt, tz=UTC):
                 # We have no sure way to figure out
                 # the timezone name, we fallback
                 # on a fixed offset
-                offset = dt.utcoffset()
-
                 tz = dt.utcoffset().total_seconds() / 3600
 
         return cls(