haproxy: patches from upstream (ssl,counter,stick-table, track)

 - BUG/MINOR: ssl: Fix external function in order not to return a pointer
   on an internal trash buffer
 - BUG/MINOR: counters: do not untrack counters before logging
 - BUG/MAJOR: sample: correctly reinitialize sample fetch context before
   calling sample_process()
 - MINOR: stick-table: make stktable_fetch_key() indicate why it failed
 - BUG/MEDIUM: counters: fix track-sc* to wait on unstable contents

Signed-off-by: Thomas Heil <heil@terminal-consulting.de>