contrib/rpm: build verbosely

The RPM build should be not use silent output -- it better be possible
to check whether the correct compiler flags were present at the build
time.

contrib/fedora/rpm/NetworkManager.spec

@@ -395,6 +395,7 @@ gtkdocize
 autoreconf --install --force
 intltoolize --automake --copy --force
 %configure \
+	--disable-silent-rules \
 	--disable-static \
 	--with-dhclient=yes \
 	--with-dhcpcd=no \