do not compress .xhtml files and remove junk files

dh_compress compresses .xhtml files by default, which breaks our doxygen
documentation. doxygen has also a bunch of temporary files it creates
which stay in the build directory and so we remove them before
installing them as documentation.

Closes: 738933

debian/rules

@@ -134,6 +134,7 @@ libapt-pkg-doc: build-debiandoc
 #
 # libapt-pkg-doc install
 #
+	rm -f $(BLD)/doc/doxygen/html/*.map $(BLD)/doc/doxygen/html/*.md5
 	dh_installdocs -p$@ $(BLD)/docs/design* \
 			    $(BLD)/docs/dpkg-tech* \
 			    $(BLD)/docs/files* \
@@ -145,7 +146,7 @@ libapt-pkg-doc: build-debiandoc
 
 	dh_installchangelogs -p$@
 	dh_strip -p$@
-	dh_compress -p$@
+	dh_compress -p$@ -X.xhtml
 	dh_fixperms -p$@
 	dh_installdeb -p$@
 	dh_gencontrol -p$@