Python: Header position should be 64-bits long
Python: Header position should be 64-bits long

Fixes MB-7347

Change-Id: Ibe6bca62d453405eb2e7a38ef2514a3c51d1732d
Reviewed-on: http://review.couchbase.org/29590
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

vmx/couchstore,vmx/couchstore,jimwwalker/couchstore,abhinavdangeti/couchstore,jimwwalker/couchstore,t3rm1n4l/couchstore,vmx/couchstore,couchbaselabs/couchstore,couchbaselabs/couchstore,abhinavdangeti/couchstore,t3rm1n4l/couchstore,t3rm1n4l/couchstore,abhinavdangeti/couchstore,jimwwalker/couchstore,couchbaselabs/couchstore