rpm: restore RPMEXTRAPROVIDE support

in commit 15205b7, the support of
RPMEXTRAPROVIDE is removed by accient, makes the rpm builds unusable.

Author: Icenowy

pm/rpm/pack

@@ -79,7 +79,7 @@ BuildRoot:	%{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 $(VER_NONE=0 rpmopttag Requires $PKGDEP)
 $(rpmopttag Conflicts $PKGCONFL)
 $(rpmopttag Obsoletes $PKGREP)
-$(rpmopttag Provides $PKGPROV)
+$(rpmopttag Provides $RPMEXTRAPROVIDE $PKGPROV $PKGPROV_RPM)
 $(rpmopttag Suggests $PKGSUG)
 
 %description