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>

libmpcdec.spec

@@ -45,9 +45,6 @@ make install DESTDIR=$RPM_BUILD_ROOT
 rm -fv $RPM_BUILD_ROOT%{_libdir}/lib*.la
 
 
-%clean
-rm -rf $RPM_BUILD_ROOT 
-
 
 %post -p /sbin/ldconfig
 %postun -p /sbin/ldconfig