vl: Clean up error reporting in chardev_init_func()

Calling error_report() in a function that takes an Error ** argument
is suspicious.  chardev_init_func() does that, and then fails without
setting an error.  Its caller main(), via qemu_opts_foreach(), is fine
with it, but clean it up anyway.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20181017082702.5581-21-armbru@redhat.com>

vl.c

@@ -2239,7 +2239,7 @@ static int chardev_init_func(void *opaque, QemuOpts *opts, Error **errp)
 
     if (!qemu_chr_new_from_opts(opts, &local_err)) {
         if (local_err) {
-            error_report_err(local_err);
+            error_propagate(errp, local_err);
             return -1;
         }
         exit(0);
@@ -4233,10 +4233,8 @@ int main(int argc, char **argv, char **envp)
                       user_creatable_add_opts_foreach,
                       object_create_initial, &error_fatal);
 
-    if (qemu_opts_foreach(qemu_find_opts("chardev"),
-                          chardev_init_func, NULL, NULL)) {
-        exit(1);
-    }
+    qemu_opts_foreach(qemu_find_opts("chardev"),
+                      chardev_init_func, NULL, &error_fatal);
 
 #ifdef CONFIG_VIRTFS
     if (qemu_opts_foreach(qemu_find_opts("fsdev"),