Init the pointer to NULL for safe free() operation.
Init the pointer to NULL for safe free() operation.

Change-Id: I93f09694956b533badd3a74df75ecc9333cae90f

sushmaad/forestdb,wurikiji/forestdb,yyangpan/forestdb,jinxuan/forestdb,couchbase/forestdb,zhaog/forestdb,zhaog/forestdb,yyangpan/forestdb,joliss/forestdb,jinxuan/forestdb,couchbase/forestdb,hisundar/forestdb,sushmaad/forestdb,wurikiji/forestdb,hisundar/forestdb,joliss/forestdb