CPack: enable statically built binaries.

@todo: Deal with this:

/build/buildd/binutils-2.20.1/builddir-single/bfd/../../bfd/plugin.c:127:
warning: Using 'dlopen' in statically linked applications requires
at runtime the shared libraries from the glibc version used for
linking
libltbox.a(tarantool.c.o): In function `main':
/home/kostja/work/tarantool/core/tarantool.c:453: warning: Using
'getpwnam' in statically linked applications requires at runtime
the shared libraries from the glibc version used for linking