Fix missing space in vitastor-cli rm-osd "still up" message

rm-osd printed "OSD 1is still up" and "OSDs 2, 3are still up" because
the verb was appended to the OSD list without a space. Also say "it"
instead of "them" when only one OSD is up.

src/cmd/cli_rm_osd.cpp

@@ -170,7 +170,8 @@ struct rm_osd_t
             }
             if (still_up.size() && !allow_up)
                 error += (still_up.size() == 1 ? "OSD " : "OSDs ") + implode(", ", still_up) +
-                    (still_up.size() == 1 ? "is" : "are") + " still up. Use `vitastor-disk purge` to delete them.\n";
+                    (still_up.size() == 1 ? " is" : " are") + " still up. Use `vitastor-disk purge` to delete " +
+                    (still_up.size() == 1 ? "it" : "them") + ".\n";
             if (is_dataloss && !force_dataloss && !dry_run)
                 error += "OSDs not deleted. Please move data to other OSDs or bypass this check with --allow-data-loss if you know what you are doing.\n";
             else if (is_warning && !force_warning && !dry_run)

tests/run_tests.sh

@@ -66,6 +66,8 @@ OLD=1 ./test_move_reappear.sh
 
 ./test_rm_degraded.sh
 
+./test_rm_osd_msg.sh
+
 ./test_snapshot_chain.sh
 SCHEME=ec ./test_snapshot_chain.sh
 ENCRYPTED=1 ./test_snapshot_chain.sh

tests/test_rm_osd_msg.sh

@@ -0,0 +1,14 @@
+#!/bin/bash -ex
+
+# Test the rm-osd message for OSDs that are still up
+
+. `dirname $0`/run_3osds.sh
+
+$VITASTOR_CLI rm-osd --dry-run 1 > ./testdata/one.txt 2>&1 && format_error "rm-osd of an up OSD was not refused"
+cat ./testdata/one.txt
+grep -q '^OSD 1 is still up\. Use `vitastor-disk purge` to delete it\.$' ./testdata/one.txt || format_error "bad message for one OSD"
+$VITASTOR_CLI rm-osd --dry-run 1 2 > ./testdata/two.txt 2>&1 && format_error "rm-osd of up OSDs was not refused"
+cat ./testdata/two.txt
+grep -q '^OSDs 1, 2 are still up\. Use `vitastor-disk purge` to delete them\.$' ./testdata/two.txt || format_error "bad message for two OSDs"
+
+format_green OK