Use git index in %autosetup (RhBug:1059285)

- Without --index in apply, any file additions will not be committed and
  in case the patch contains *only* file addition the macro can fail
  completely (empty commit). With --index there's no need for -a in
  commit either.

macros.in

@@ -1075,8 +1075,8 @@ done \
 	--author "%{__scm_author}" -m "%{name}-%{version} base"
 
 %__scm_apply_git(qp:m:)\
-%{__git} apply %{-p:-p%{-p*}} -\
-%{__git} commit %{-q} -a -m %{-m*} --author "%{__scm_author}"
+%{__git} apply --index %{-p:-p%{-p*}} -\
+%{__git} commit %{-q} -m %{-m*} --author "%{__scm_author}"
 
 # Quilt
 %__scm_setup_quilt(q) %{nil}