Fix few fedora packaging violation
* Package uses either %{buildroot} or $RPM_BUILD_ROOT
Note: Using both %{buildroot} and $RPM_BUILD_ROOT
See: http://fedoraproject.org/wiki/Packaging/Guidelines#macros
* Uses parallel make %{?_smp_mflags} macro.
- parallel make works well with talloc, tevent, tdb and samba
* Spec use %global instead of %define unless justified.
Note: %define requiring justification: %define talloc_version 2.0.8,
%define tdb_version 1.3.3, %define tevent_version 0.9.17