Correct the comment for doc_count field in fdb_file_info
Correct the comment for doc_count field in fdb_file_info

Change-Id: I3c2ab3aa64ba830f6552ad8cd14314594c14db5e

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