decom: remove brewster incl. mgmt

puppet decom in Change-Id: I4dc76fe4a

back to also removing mgmt right away
per Chris

RT #6133

Change-Id: I62d1e1aaf2f88329e3f9b33701797373175ddc2d
remove ms6 ipmi, decom

RT #7237

Change-Id: Idf410b3e02a3441d4917ad6928e7e0243d65209b