engine: Update os-info max memory sizes for x64 systems

64-bit RHEL and windows systems inherited max memory size from "other"
system which specified appropriate value for 32-bit systems (64000M).

Updated value of os.resource.maximum.ram for the following systems:

  RHEL3x64:     128 GB
  RHEL4x64:     256 GB
  RHEL5x64:     1 TB
  RHEL6x64:     3 TB
  RHEL7x64:     3 TB

  Windows2003x64:       1 TB
  Windows2008x64:       1 TB
  Windows2008R2x64:     2 TB
  Windows2012x64        4 TB
  Windows7x64:          192 GB
  Windows8x64:          512 GB

Based on:
  [1] https://access.redhat.com/articles/rhel-limits
  [2] http://msdn.microsoft.com/en-us/library/windows/desktop/aa366778(v=vs.85).aspx

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1087745
Change-Id: Ib2b098fb0c05cca5d5f9638c7ac693c631317b2f
Signed-off-by: Martin Betak <mbetak@redhat.com>