trace: no need to call trace_backend_init in different branches now

original idea to split calling locations was to spawn tracing thread
in the final child process according to

    commit 8a745f2a
    Author: Michael Mueller
    Date:   Mon Sep 23 16:36:54 2013 +0200

os_daemonize is now on top of both locations. Drop unneeded ifs.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1452174932-28657-5-git-send-email-den@openvz.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

vl.c

@@ -4110,10 +4110,8 @@ int main(int argc, char **argv, char **envp)
         qemu_set_log(mask);
     }
 
-    if (!is_daemonized()) {
-        if (!trace_init_backends()) {
-            exit(1);
-        }
+    if (!trace_init_backends()) {
+        exit(1);
     }
 
     /* If no data_dir is specified then try to find it relative to the
@@ -4657,12 +4655,6 @@ int main(int argc, char **argv, char **envp)
 
     os_setup_post();
 
-    if (is_daemonized()) {
-        if (!trace_init_backends()) {
-            exit(1);
-        }
-    }
-
     main_loop();
     replay_disable_events();