Initialize err pointer to SUCCESS for new durability context
Initialize err pointer to SUCCESS for new durability context

This way it's safe to check the error code from the 'out' pointer`

Change-Id: I456d2c70dd7599452bb7d95fdafc3033fa9e91d0
Reviewed-on: http://review.couchbase.org/51053
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Subhashni Balakrishnan <7129c8e37b832c7bd362ff375532d24b98ef5162@gmail.com>

couchbase/libcouchbase,senthilkumaranb/libcouchbase,avsej/libcouchbase,mody/libcouchbase,couchbase/libcouchbase,mody/libcouchbase,maxim-ky/libcouchbase,kojiromike/libcouchbase,kojiromike/libcouchbase,avsej/libcouchbase,kojiromike/libcouchbase,PureSwift/libcouchbase,PureSwift/libcouchbase,couchbase/libcouchbase,maxim-ky/libcouchbase,maxim-ky/libcouchbase,avsej/libcouchbase,signmotion/libcouchbase,kojiromike/libcouchbase,senthilkumaranb/libcouchbase,avsej/libcouchbase,senthilkumaranb/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,avsej/libcouchbase,signmotion/libcouchbase,mody/libcouchbase,signmotion/libcouchbase,PureSwift/libcouchbase,mody/libcouchbase,PureSwift/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,senthilkumaranb/libcouchbase,avsej/libcouchbase,avsej/libcouchbase,signmotion/libcouchbase,maxim-ky/libcouchbase