Fix distcheck.

* Uninstall the docs if they were installed.
* Remember to distribute Doxyfile and vdpau_data_flow.png in the
  tarball.
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>

doc/Makefile.am

 all: html
 install-data-local: install-html
 
+EXTRA_DIST = \
+    Doxyfile \
+    vdpau_data_flow.png
+
 VDPAU_HEADER_DIR := $(top_srcdir)/include
 VDPAU_HEADER_FILES := \
     $(VDPAU_HEADER_DIR)/vdpau/vdpau.h \
@@ -14,8 +18,10 @@ html-out/%: Doxyfile $(VDPAU_HEADER_FILES)
 if ENABLE_DOCS
 html: html-out/index.html
 install-html-local:
-	$(install_sh) -d $(DESTDIR)$(docdir)/html
-	$(install_sh) -m 644 html-out/* $(DESTDIR)$(docdir)/html
+	$(install_sh) -d "$(DESTDIR)$(docdir)/html"
+	$(install_sh) -m 644 html-out/* "$(DESTDIR)$(docdir)/html"
+uninstall-local:
+	$(RM) -r "$(DESTDIR)$(docdir)/html"
 endif
 
 clean-local: