Removed all occurences of crc32 in dbo_source as a cache key,
 which is not only a stupid idea but should be actually considered a bug!
It does collide with a .1% propability for every 1.6mio queries processed
(which is not to uncommon in a shell process).
Removed crc32() because of *very* common collisions occuring.

Does not touch any of the exposed stuff and will not break anything
else (except you know of a collision within crc32 already and make
"use" of it - which can only be malcious.)

Has already been "fixed" in the 2.x branch.
Merge pull request #4368 from hmic/1.3-dbo_source-NO-crc32

1.3 dbo source no crc32