Fix BM homebrew compatibility (rptrid comparison)

BM switched from upper case to lower case hexadecimal representation in
BrandMeister release 20190421-185653.

The comparison must be case insensitive according to a member of the BM
dev team (@cyanide-burnout) on Telegram:
"it shoud check on case-insensetive way".

homebrew/homebrew.go

@@ -254,7 +254,8 @@ func (h *Homebrew) WriteToPeerWithID(b []byte, id uint32) error {
 }
 
 func (h *Homebrew) checkRepeaterID(id []byte) bool {
-	return id != nil && bytes.Equal(id, h.id)
+	// BrandMeister release 20190421-185653 switched from upper case to lower case hex digits
+	return id != nil && bytes.EqualFold(id, h.id)
 }
 
 func (h *Homebrew) getPeer(id uint32) *Peer {