Bug#913447: libgap-sage: Depends on nbs version of gap

[Jeremy Bicha]

Source: libgap-sage
Version: 4.8.8+6+20181010g0581647+dsx-1
Severity: serious
X-Debbugs-CC: calculus at rezozer.net

libgap-sage-4 has this dependency:
Depends: gap (>= 4r8p8), gap (<< 4r8p9)

But the version of gap in unstable is 4r9p3-3.

I've filing this as serious since version 4r8p8 is no longer built
from source (NBS) in unstable.

Thanks,
Jeremy Bicha