Tidy up suricata package about build-suricata

[philrz]

Verified with the suricata-v5.0.3-brim25 artifact on macOS.

Short of enumerating every file that's been trimmed, here's a macro-level view. As of the suricata-v5.0.3-brim21 artifact that pre-dated this enhancement:

suricata-v5.0.3-brim21$ find . | wc -l
     223

Then with the suricata-v5.0.3-brim25 artifact:

suricata-v5.0.3-brim25$ find . | wc -l
      62

Obviously it's important that none of the trimmed files caused us to lose functionality, but we'll be keeping an eye on that as we continue testing as we finalize the introduction of Suricata to Brim.

Thanks @henridf!