[NTOS]: Minor fixes:

[NTOS]: Minor fixes:
- Correctly specify the buffer size for RtlInitEmptyUnicodeString calls;
- Prefer using RtlAppendUnicodeStringToString instead of RtlAppendStringToString: both actually do the very same job on counted strings, but the former doesn't need the explicit PSTRING casts, and NULL-terminate the string buffer if possible (aka. if the available remaining length permits it, otherwise it doesn't add any NULL terminator, falling back to the default behaviour of RtlAppendStringToString).
- Remove a deprecated commented-out variable.

svn path=/trunk/; revision=74708