[oe] svn:// fetcher do not checkout repository at every build

[Hauser, Wolfgang (external)]

Hello,

as pointed in the bitbake user manual, the svn fetcher should checkout a
repository at every build if SRCDATE is set to "now".

If I want to use that in OE (for our local applications), always the
archive for the repository, stored in download cache, is used instead of
doing a new checkout. (I user bb 1.8.18)

Is it possible to turn off the download cache check for a recipe ? 

Regards
Wolfgang Hauser