lib: preserve: don't delete file's on package removal

The old behaviour was to only respect `preserve` on package updates.

This leads to issues where `vkpurge` would not be able to remove other
files not part of a kernel package when an obsolete kernel package was
removed using `xbps-remove -o`.

So for consistency `preserve` in a packages properties always means
`preserve`.

Author: Duncaen

lib/transaction_files.c

@@ -247,7 +247,7 @@ collect_obsoletes(struct xbps_handle *xhp)
 			 * new package.
 			 * Probably obsolete.
 			 */
-			if (item->old.preserve && item->old.update) {
+			if (item->old.preserve) {
 				xbps_dbg_printf("[files] %s: skipping `preserve` %s: %s\n",
 				    item->old.pkgver, typestr(item->old.type), item->file);
 				continue;

tests/xbps/libxbps/shell/preserve_test.sh

@@ -85,7 +85,60 @@ preserve_update_conflict_body() {
 	atf_check_equal $? 0
 }
 
+atf_test_case preserve_remove
+
+preserve_remove_head() {
+	atf_set "descr" "Tests for pkg removal with preserve"
+}
+
+preserve_remove_body() {
+	mkdir some_repo
+	mkdir -p pkg_A/1.0
+	echo "blahblah" > pkg_A/1.0/blah
+	echo "foofoo" > pkg_A/1.0/foo
+
+	cd some_repo
+	xbps-create -A noarch -n A-1.0_1 -s "A pkg" --preserve ../pkg_A
+	atf_check_equal $? 0
+	xbps-rindex -d -a $PWD/*.xbps
+	atf_check_equal $? 0
+	cd ..
+
+	xbps-install -r root --repository=$PWD/some_repo -yd A
+	atf_check_equal $? 0
+
+	cd some_repo
+	mv ../pkg_A/1.0 ../pkg_A/1.1
+	rm -f *.xbps
+	xbps-create -A noarch -n A-1.1_1 -s "A pkg" --preserve ../pkg_A
+	atf_check_equal $? 0
+	xbps-rindex -d -a $PWD/*.xbps
+	atf_check_equal $? 0
+	cd ..
+
+	xbps-install -r root --repository=$PWD/some_repo -yd A
+	atf_check_equal $? 0
+
+	rv=0
+	[ -e root/1.0/blah -a -e root/1.0/blah ] || rv=1
+	[ -e root/1.1/blah -a -e root/1.1/blah ] || rv=2
+	atf_check_equal $rv 0
+
+	xbps-remove -r root -yd A
+	atf_check_equal $? 0
+
+	rv=0
+	[ -e root/1.0/blah -a -e root/1.0/blah ] || rv=1
+	[ -e root/1.1/blah -a -e root/1.1/blah ] || rv=2
+	atf_check_equal $rv 0
+
+	xbps-pkgdb -r root -av
+	atf_check_equal $? 0
+}
+
+
 atf_init_test_cases() {
 	atf_add_test_case preserve_update
 	atf_add_test_case preserve_update_conflict
+	atf_add_test_case preserve_remove
 }