[spec] Tolerate rpm builds without generating doxygen docs

Temporarily disabling generation of doxygen documentation can significantly
reduce time taken by full rebuilds. However, it also makes rpm build fail
due to not having any html documents to install / package after build step.

Produce empty doc package if no html files have been generated during
build step.

Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

rpm/usb-moded.spec

@@ -314,7 +314,9 @@ install -m 644 -D src/usb_moded-appsync-dbus.h %{buildroot}/%{_includedir}/%{nam
 install -m 644 -D src/com.meego.usb_moded.xml %{buildroot}/%{_includedir}/%{name}/com.meego.usb_moded.xml
 install -m 644 -D usb_moded.pc %{buildroot}/%{_libdir}/pkgconfig/usb_moded.pc
 install -d %{buildroot}/%{_docdir}/%{name}-%{version}/html/
-install -m 644 docs/html/* %{buildroot}/%{_docdir}/%{name}-%{version}/html/
+if [ -f docs/html/index.html ]; then
+  install -m 644 docs/html/* %{buildroot}/%{_docdir}/%{name}-%{version}/html/
+fi
 install -m 644 docs/usb_moded-doc.txt %{buildroot}/%{_docdir}/%{name}-%{version}/
 install -m 644 -D debian/manpage.1 %{buildroot}/%{_mandir}/man1/usb-moded.1
 install -m 644 -D debian/usb_moded.conf %{buildroot}/%{_sysconfdir}/dbus-1/system.d/usb_moded.conf