When closing a (shared-cache) database connection, be sure to clear out
all KeyInfo objects cached on Index objects. 
Fix for ticket [e4a18565a36884b00edf].
Increase the version number to 3.8.7.3.
The KeyInfo cache must be cleared before closing the btree, not after.
Revised fix for ticket [e4a18565a36884b00edf].
Fix a buffer overread that might occur in analyze.c if SQLITE_ENABLE_STAT4 was defined.
Version 3.8.7.3