Two things:

at least on the system where I'm trying this (SLES 11), --without geo-replication is ignored by rpmbuild and the macro is not set. I suspect this has something to do with the corresponding macro having a dash in its name (%_without_geo-replication). The result is that geo replication is always built even if it's not wanted. My provisional fix (for lack of a better one) is to not use the dash:

--without georeplication

and rename the macro to %_without_georeplication. This works.

However, when doing so, the second issue appears: at line 243 there is a lone

%post geo-replication

macro, which fails when geo-replication is disabled (package doesn't exist). My solution was to wrap that with the conditional that checks if geo-replication is wanted:

%if 0%{!?_without_georeplication:1}
%post geo-replication
#restart glusterd.
/etc/init.d/glusterd restart &> /dev/null
%endif

...