[storm] probable bug in storm/0.19/storm.twisted.transact causes high db locks.

[Giovanni `evilaliv3` Pellerano]

While debugging some code of the Globaleaks software i've probably
found a bug related to storm integration with twisted.

in reference to storm/0.19/storm.twisted.transact, the
time.sleep(seconds) inside @transact decorator causes a long db lock
in case of exceptions.

in my opinion, the retry mechanism needs to be implemented outside of
the @transact method and not vice versa. 	furthermore a sleep
expressed in seconds is probably too long for a transaction retry.

here are some reference to the issue and to the temporary fix:
https://github.com/globaleaks/GLBackend/issues/44
https://github.com/globaleaks/GLBackend/commit/aec7e6902ed64ba33f856ca6bd69aa049a6cf64d

best regards,

Giovanni `evilaliv3` Pellerano