Fix DBMS name/version reporting fallback and resume detection

[tanaydin]

Summary

• Format.getDbms() / Backend.getDbms() now fall back to conf.dbms when kb.dbms isn't set yet, so a formatted DBMS+version string no longer drops the DBMS name or prints "None" before fingerprinting completes.
• _resumeDBMS() in lib/core/target.py now also propagates the DBMS/version into Backend when resuming a session where the DBMS wasn't previously stored, and preserves the previously detected version when the resumed value is unknown.
• Minor simplification cleanups in lib/core/option.py (non-SQL technique switch validation, tamper priority check, kb.chars/kb.multibit initialization).
• Added unit tests in tests/test_misc.py covering the Format.getDbms() fallback behavior.

Test plan

• python tests/test_misc.py (new TestFormatGetDbms cases pass)

[stamparm]

that is not how this is done. changing 4 files for sqlmap, without even opening an issue or asking whether you could do it will always result with close down

[stamparm]

you really think that i could merge something like Minor simplification cleanups in lib/core/option.py (non-SQL technique switch validation, tamper priority check, kb.chars/kb.multibit initialization). without any issue where you explain "your problem" first? no way

[tanaydin]

Ok, I'll try to provide a working test for this, it's hard to reproduce, "sometimes" I'm hitting that bug.

[stamparm]

man, you open an issue describing your "problem", then you leave me to try to fix it. if i get stuck (i doubt it), you can do your pull request. that's the way this story goes. this is wrong repo for gaining merge points

[tanaydin]

not looking for gain any points. will track correct way. thank you for explanation.