Remove superfluous '\n' around error_report()

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/trace/control.c b/trace/control.c
index 0d30801..995beb3 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -126,7 +126,7 @@
                     error_report("WARNING: trace event '%s' does not exist",
                                  line_ptr);
                 } else if (!trace_event_get_state_static(ev)) {
-                    error_report("WARNING: trace event '%s' is not traceable\n",
+                    error_report("WARNING: trace event '%s' is not traceable",
                                  line_ptr);
                 } else {
                     trace_event_set_state_dynamic(ev, enable);