CCBC-104 Fix illegal memory access
CCBC-104 Fix illegal memory access

==19659==  General Protection Fault
==19659==    at 0x4E93216: ringbuffer_write (ringbuffer.c:127)
==19659==    by 0x4E90ACA: relocate_packets (instance.c:523)
==19659==    by 0x4E90E5E: lcb_update_serverlist (instance.c:583)
==19659==    by 0x4E91B83: vbucket_stream_handler (instance.c:964)
==19659==    by 0x60B7599: event_base_loop (in /usr/lib64/libevent-1.4.so.2.1.3)
==19659==    by 0x5EB0320: lcb_io_run_event_loop (plugin-libevent.c:320)
==19659==    by 0x4E982B4: lcb_wait (wait.c:112)

Change-Id: I6d8657433665b74ec5700f7665103f346bcfd46b
Reviewed-on: http://review.couchbase.org/22691
Tested-by: Sergey Avseyev <87f6d5e4fd3644c3c20800cde7fd3ad1569370b3@gmail.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

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