IMPALA-2761: OS X: HashTable: Rename PAGE_SIZE macro
IMPALA-2761: OS X: HashTable: Rename PAGE_SIZE macro

PAGE_SIZE is a macro that is already used to get the main memory page
size. However, on Linux we haven't run into issues redefining it. On Mac
OS X it will fail compiling. To avoid this, rename to HT_PAGE_SIZE.

Change-Id: Id110fca63c20a7dafc486ea719727137bb4eb2cd
Reviewed-on: http://gerrit.cloudera.org:8080/1610
Reviewed-by: Martin Grund <2546548d516fa64c411fde8242af35f3f80ad31f@cloudera.com>
Readability: Martin Grund <2546548d516fa64c411fde8242af35f3f80ad31f@cloudera.com>
Reviewed-by: Michael Ho <43544f6c6f19372b140301f92a3768afc300868a@cloudera.com>
Tested-by: Internal Jenkins

ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC