silenced some clang warnings

ot_clean.c

@@ -100,7 +100,7 @@ int clean_single_torrent( ot_torrent *torrent ) {
 /* Clean up all peers in current bucket, remove timedout pools and
  torrents */
 static void * clean_worker( void * args ) {
-  args=args;
+  (void) args;
   while( 1 ) {
     int bucket = OT_BUCKET_COUNT;
     while( bucket-- ) {

ot_fullscrape.c

@@ -57,7 +57,7 @@ static void * fullscrape_worker( void * args ) {
   int iovec_entries;
   struct iovec *iovector;
 
-  args = args;
+  (void) args;
 
   while( 1 ) {
     ot_tasktype tasktype = TASK_FULLSCRAPE;

ot_stats.c

@@ -566,7 +566,7 @@ size_t stats_return_tracker_version( char *reply ) {
 }
 
 size_t return_stats_for_tracker( char *reply, int mode, int format ) {
-  format = format;
+  (void) format;
   switch( mode & TASK_TASK_MASK ) {
     case TASK_STATS_CONNS:
       return stats_connections_mrtg( reply );
@@ -725,7 +725,7 @@ static void * stats_worker( void * args ) {
   int iovec_entries;
   struct iovec *iovector;
 
-  args = args;
+  (void) args;
 
   while( 1 ) {
     ot_tasktype tasktype = TASK_STATS;