_fdb_sync_db_header() bug fix
_fdb_sync_db_header() bug fix

- FDB handle's current revision number was not updated.
- If ID-tree is used instead of HB+Trie due to custom compare
function, the root BID of ID-tree was not updated.

Change-Id: I7967f6cdc13a98cda5d9120a4231a3f6faf9a86f

hisundar/forestdb,zhaog/forestdb,yyangpan/forestdb,sushmaad/forestdb,zhaog/forestdb,wurikiji/forestdb,joliss/forestdb,seem-sky/forestdb,uvenum/forestdb,yyangpan/forestdb,sushmaad/forestdb,jinxuan/forestdb,nvoron23/forestdb,seem-sky/forestdb,uvenum/forestdb,couchbase/forestdb,hisundar/forestdb,nvoron23/forestdb,wurikiji/forestdb,joliss/forestdb,jinxuan/forestdb,couchbase/forestdb