srtp: Fix a warning.

srtp/test/replay_driver.c

 /*
  * replay_driver.c
  *
  * A driver for the replay_database implementation
  *
  * David A. McGrew
  * Cisco Systems, Inc.
  */
 
 /*
@@ skipping 215 matching lines @@
 #include <time.h>       /* for clock()  */
 #include <stdlib.h>     /* for random() */
 
 #define REPLAY_NUM_TRIALS 10000000
 
 double
 rdb_check_adds_per_second(void) {
   uint32_t i;
   rdb_t rdb;
   clock_t timer;
-  int failures;                    /* count number of failures        */
+  int failures = 0;                    /* count number of failures        */
   
   if (rdb_init(&rdb) != err_status_ok) {
     printf("rdb_init failed\n");
     exit(1);
   }  
 
   timer = clock();
   for(i=0; i < REPLAY_NUM_TRIALS; i+=3) {
     if (rdb_check(&rdb, i+2) != err_status_ok)
       ++failures;
     if (rdb_add_index(&rdb, i+2) != err_status_ok)
       ++failures;
     if (rdb_check(&rdb, i+1) != err_status_ok)
       ++failures;
     if (rdb_add_index(&rdb, i+1) != err_status_ok)
       ++failures;
     if (rdb_check(&rdb, i) != err_status_ok)
       ++failures;
     if (rdb_add_index(&rdb, i) != err_status_ok)
       ++failures;
   }
   timer = clock() - timer;
 
   return (double) CLOCKS_PER_SEC * REPLAY_NUM_TRIALS / timer;
 }