Remove misleading BuildRequires

If sources are built using `dist`, `rpmstuff` or `debstuff`, current
version of MKit does not actually require git--all that is necessary
should be cached in the tarball anyway.

Regarding coreutils, they are part of essential set on most
distributions; on those, one should actually refrain from specifying
them.

src/stub

             echo 'Source0:	%{name}-%{version}.tar.gz'
             echo ''
             echo 'BuildArch:	noarch'
-            echo 'BuildRequires:	coreutils git'
             echo 'Requires:	MKIT_STUB_REQUIRES'
             echo ''
             echo '%description'