NETAPI x64 Fixes

NETAPI post module on x64 (Windows 8.1/Windows2k12 especially) will cause errors/crash meterpreter.

use post/windows/gather/credentials/gpp
use post/windows/gather/enum_domain_users

both have issues as a result. Possibly other enum_domain* post modules. 

We should use entriesread instead of totalentries incase we dont get all the values back! 

## Verification
- [ ] No longer crashes on x64 and doesn't crash on x86

* Get an x64 meterpreter on a Win2k12 box/Win8.1 (On a domain preferably)
* use post/windows/gather/enum_domain_users
* set SESSION 1
* set HOST 127.0.0.1
- [ ] run should return current logged in user

* use post/windows/gather/enum_domains
* set SESSION 1
- [ ] run should return a list of DCs


* Get an x86 shell on a Win2k12 box/Win8.1 (On a domain preferably)
* use post/windows/gather/enum_domain_users
* set SESSION 2
* set HOST 127.0.0.1
- [ ] run should return current logged in user

* use post/windows/gather/enum_domains
* set SESSION 2
- [ ] run should return a list of DCs







Happy with either, existing railgun code uses this.