* final.py: Import 'support.py' for the side-effect of checking the
GnuPG version.
* t-data.py: Likewise.
* t-protocol-assuan.py: Likewise.
* t-wrapper.py: Likewise.
* t-callbacks.py: Avoid warning about 'support' being unused.
* t-edit.py: Likewise.
* t-encrypt-sym.py: Likewise.
* t-file-name.py: Likewise.
* t-idiomatic.py: Likewise.
* t-sig-notation.py: Likewise.
* t-trustlist.py: Likewise.
* t-verify.py: Likewise.
* t-wait.py: Likewise.
* t-keylist-from-data.py: Trim unused imports.