pw_doctor: Remove Pigweed branding
pw_doctor: Remove Pigweed branding

This removes an instance of the Pigweed name from the environment setup
process, to better facilitate whitelabelling Pigweed.

Change-Id: Ia444b854dce9c87eaa95551c55dda98d2dea6ae0

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed