Fix coverity issues in execHHashagg.c
Fix coverity issues in execHHashagg.c

CID 167715: Incorrect Expression (UNINTENDED_INTEGER_DIVISION)
Covertiy reported that a division operation of two integers is then
converted to a double. This would cause any fractional part of the
quotient to be lost. This is fixed by casting the divisor to a double
before the division.

CID 167714: Dereference before null check (REVERSE_INULL)
Coverity reported that a null check is unnecessary because the pointer
spill_file->file_info is dereferenced before this line in every code
path. This issue is fixed by removing the null pointer check

xinzweb/gpdb,yuanzhao/gpdb,xinzweb/gpdb,Quikling/gpdb,edespino/gpdb,greenplum-db/gpdb,Quikling/gpdb,50wu/gpdb,Quikling/gpdb,kaknikhil/gpdb,edespino/gpdb,Quikling/gpdb,yuanzhao/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,50wu/gpdb,Chibin/gpdb,xinzweb/gpdb,lisakowen/gpdb,kaknikhil/gpdb,janebeckman/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,adam8157/gpdb,jmcatamney/gpdb,janebeckman/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,xinzweb/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,yuanzhao/gpdb,rvs/gpdb,rvs/gpdb,Chibin/gpdb,rvs/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,lisakowen/gpdb,edespino/gpdb,Chibin/gpdb,rvs/gpdb,edespino/gpdb,Quikling/gpdb,janebeckman/gpdb,rvs/gpdb,rvs/gpdb,yuanzhao/gpdb,Chibin/gpdb,xinzweb/gpdb,edespino/gpdb,janebeckman/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,edespino/gpdb,jmcatamney/gpdb,50wu/gpdb,rvs/gpdb,janebeckman/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,lisakowen/gpdb,greenplum-db/gpdb,Quikling/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,cjcjameson/gpdb,Quikling/gpdb,jmcatamney/gpdb,xinzweb/gpdb,janebeckman/gpdb,cjcjameson/gpdb,Chibin/gpdb,edespino/gpdb,janebeckman/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,janebeckman/gpdb,adam8157/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,Chibin/gpdb,adam8157/gpdb,edespino/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,janebeckman/gpdb,50wu/gpdb,adam8157/gpdb,Chibin/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,cjcjameson/gpdb,edespino/gpdb,yuanzhao/gpdb,janebeckman/gpdb,lisakowen/gpdb,Chibin/gpdb,Quikling/gpdb,edespino/gpdb,greenplum-db/gpdb,xinzweb/gpdb,rvs/gpdb,rvs/gpdb,Quikling/gpdb,rvs/gpdb,kaknikhil/gpdb,xinzweb/gpdb,adam8157/gpdb,lisakowen/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,lisakowen/gpdb,Chibin/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,Quikling/gpdb,kaknikhil/gpdb,Chibin/gpdb