contrib/rpm: explicitly enable/disable bluetooth support

The bluetooth plugin (with BlueZ5/NAP support) always gets
build, but DUN support requires a library.

When enabling build of the bluetooth subpackage, then always
enable DUN support. And enable it explicitly, especially meson
would not autodetect support and disable it by default.

(cherry picked from commit 30f6a5dd21)

contrib/fedora/rpm/NetworkManager.spec

@@ -550,6 +550,11 @@ NetworkManager in cloud setups. Currently only EC2 is supported.
 %else
 	-Diwd=false \
 %endif
+%if %{with bluetooth}
+	-Dbluez5_dun=true \
+%else
+	-Dbluez5_dun=false \
+%endif
 %if %{with nmtui}
 	-Dnmtui=true \
 %else
@@ -676,6 +681,11 @@ intltoolize --automake --copy --force
 %else
 	--with-iwd=no \
 %endif
+%if %{with bluetooth}
+	--enable-bluez5-dun=yes \
+%else
+	--enable-bluez5-dun=no \
+%endif
 %if %{with nmtui}
 	--with-nmtui=yes \
 %else