debian: remove obsolete ceph-base.docs, restore dh_installdocs

debian/ceph-base.docs only referred to a README that doesn't exist, so
remove it. Because dpkg-source doesn't reflect deletions from debian/
cf the orig.tar.gz, also remove the file in dh_auto_clean.

Then do away with the removal of the empty override of dh_installdocs;
the main benefit of which here is that debian/copyright gets installed
in all of the built packages, which otherwise lack a copyright
file.

Signed-off-by: Matthew Vernon <[email protected]>

debian/rules

@@ -70,7 +70,7 @@ override_dh_auto_build:
 
 override_dh_auto_clean:
 	dh_auto_clean --buildsystem=cmake
-	rm -f debian/radosgw.init debian/ceph.logrotate
+	rm -f debian/radosgw.init debian/ceph.logrotate debian/ceph-base.docs
 
 override_dh_auto_install:
 	dh_auto_install --buildsystem=cmake --destdir=$(DESTDIR)
@@ -86,8 +86,6 @@ override_dh_auto_install:
 override_dh_installchangelogs:
 	dh_installchangelogs --exclude doc/changelog
 
-override_dh_installdocs:
-
 override_dh_installlogrotate:
 	cp src/logrotate.conf debian/ceph-common.logrotate
 	dh_installlogrotate -pceph-common
@@ -149,4 +147,4 @@ override_dh_python3:
 # do not run tests
 override_dh_auto_test:
 
-.PHONY: override_dh_autoreconf override_dh_auto_configure override_dh_auto_build override_dh_auto_clean override_dh_auto_install override_dh_installdocs override_dh_installlogrotate override_dh_installinit override_dh_strip override_dh_auto_test
+.PHONY: override_dh_autoreconf override_dh_auto_configure override_dh_auto_build override_dh_auto_clean override_dh_auto_install override_dh_installlogrotate override_dh_installinit override_dh_strip override_dh_auto_test