Merge remote-tracking branch 'origin/topic/vlad/gh-1286'

Merge adjustments:
- Rewrote the check for error response as a switch statement to
  fix compiler warning about signed/unsigned comparison and also
  to just simplify/clarify the logic.
- Changed the btest to use `zeek -b`.

* origin/topic/vlad/gh-1286:
  Add tests for new SMB3 multichannel support
  Fix SMB2 response status parsing. Fixes #1286

testing/btest/scripts/base/protocols/smb/smb3-multichannel.test

@@ -0,0 +1,8 @@
+# @TEST-EXEC: zeek -b -r $TRACES/smb/smb3_multichannel.pcap %INPUT
+# @TEST-EXEC: btest-diff smb_files.log
+# @TEST-EXEC: test ! -f dpd.log
+# @TEST-EXEC: test ! -f weird.log
+
+@load base/protocols/smb
+
+