mount-tool: return 0 instead of NULL in the acquire_description() (#4009)

to prevent:

src/mount/mount-tool.c: In function ‘acquire_description’:
src/mount/mount-tool.c:728:24: warning: return makes integer from pointer without a cast [-Wint-conversion]
                 return NULL;
                                         ^~~~
warning.

Additionally we don't set Description property in a case when
arg_description is NULL.

1 files changed, 6 insertions, 4 deletions

diff --git a/src/mount/mount-tool.c b/src/mount/mount-tool.c
index 9076ba3b0b..80bba086e4 100644
--- a/src/mount/mount-tool.c
+++ b/src/mount/mount-tool.c
@@ -319,9 +319,11 @@ static int parse_argv(int argc, char *argv[]) {
 static int transient_unit_set_properties(sd_bus_message *m, char **properties) {
         int r;
 
-        r = sd_bus_message_append(m, "(sv)", "Description", "s", arg_description);
-        if (r < 0)
-                return r;
+        if (!isempty(arg_description)) {
+                r = sd_bus_message_append(m, "(sv)", "Description", "s", arg_description);
+                if (r < 0)
+                        return r;
+        }
 
         if (arg_bind_device && is_device_path(arg_mount_what)) {
                 _cleanup_free_ char *device_unit = NULL;
@@ -725,7 +727,7 @@ static int acquire_description(struct udev_device *d) {
         else if (model)
                 arg_description = strdup(model);
         else
-                return NULL;
+                return 0;
 
         if (!arg_description)
                 return log_oom();