Remove %clean section

None of currently supported distributions need that.
Last one was EL5 which is EOL for a while.

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

gavl.spec

@@ -74,9 +74,6 @@ find $RPM_BUILD_ROOT -name '*.la' -exec rm -f {} ';'
 touch -r include/gavl/gavl.h $RPM_BUILD_ROOT%{_includedir}/gavl/gavl_version.h
 
 
-%clean
-rm -rf $RPM_BUILD_ROOT
-
 
 %post -p /sbin/ldconfig