Change BB_EXTRA_VERSION: now it needs to contain any spaces/parenthesis

Before this change, BB_EXTRA_VERSION of "" resulted in:

	"BusyBox v1.28.0.git () multi-call binary"

message, after the fix it is:

	"BusyBox v1.28.0.git multi-call binary"

While at it, eliminate BB_BT and BANNER single-use macros.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2 files changed