Don't start the file logger when syslog is specified.

If --syslog is specified on the commandline then vlc loads the logger in file mode first, because --file-logging is the default. This is counter intuitive for users, they expect *only* syslog mode to be active. Note that the logger module can only have one mode active at the sametime, either html, text or syslog.
(cherry picked from commit 5e2f7b2f90dbab0488d62557ba59159925a88e3a)

src/libvlc.c

@@ -858,7 +858,8 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
     }
 #endif
 
-    if( config_GetInt( p_libvlc, "file-logging" ) > 0 )
+    if( (config_GetInt( p_libvlc, "file-logging" ) > 0) &&
+        !config_GetInt( p_libvlc, "syslog" ) )
     {
         libvlc_InternalAddIntf( p_libvlc, "logger,none" );
     }