bomb: Eliminate bombcomm[], it's redundant

bomb: Eliminate bombcomm[], it's redundant

bombcomm[] used to contain the commodities that can be p-bombed.  In
BSD Empire 1.1, it contained I_SHELL, I_GUN, I_MILIT, I_PETROL, I_OIL,
I_RAD.  In Chainsaw, it contained either everything or everything but
I_BAR, depending on option preprocessor symbol SUPER_BARS.  When
Empire 2 replaced the compile time variable SUPER_BARS by the run time
variable opt_SUPER_BARS, bombcomm[] became a redundant indirection.
Eliminate it.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>