version number: 0.98 -> 0.98-git. @bjourne suggested, some python projects do this too.
Revert "version number: 0.98 -> 0.98-git. @bjourne suggested, some python projects do this too."

This reverts commit 599c2cdba265004cad444e1f4e6651e19b143661.

XXX: Mac fails with this error:

c++ -Wall -DFACTOR_VERSION="0.98-git" -DFACTOR_GIT_LABEL="heads/master-0-g599c2cd" -fomit-frame-pointer -mmacosx-version-min=10.5 -m64 -O3 -g -dynamiclib -single_module -current_version 0.98-git -compatibility_version 0.98-git -fvisibility=hidden -lm -framework Cocoa -framework AppKit -o libfactor.dylib vm/os-unix.o vm/os-macosx.o vm/mach_signal.o vm/mvm-unix.o vm/cpu-x86.o vm/aging_collector.o vm/alien.o vm/arrays.o vm/bignum.o vm/byte_arrays.o vm/callbacks.o vm/callstack.o vm/code_blocks.o vm/code_heap.o vm/compaction.o vm/contexts.o vm/data_heap.o vm/data_heap_checker.o vm/debug.o vm/dispatch.o vm/entry_points.o vm/errors.o vm/factor.o vm/free_list.o vm/full_collector.o vm/gc.o vm/gc_info.o vm/image.o vm/inline_cache.o vm/instruction_operands.o vm/io.o vm/jit.o vm/math.o vm/mvm.o vm/nursery_collector.o vm/object_start_map.o vm/objects.o vm/primitives.o vm/quotations.o vm/run.o vm/safepoints.o vm/sampling_profiler.o vm/strings.o vm/to_tenured_collector.o vm/tuples.o vm/utilities.o vm/vm.o vm/words.o
ld: malformed 32-bit x.y.z version number: 0.98-git
clang: error: linker command failed with exit code 1 (use -v to see invocation)