Remove unused variables

test/default/scalarmult2.c

@@ -13,7 +13,6 @@ main(void)
 {
     unsigned char bobpk[32];
     char          hex[65];
-    int           i;
 
     crypto_scalarmult_base(bobpk, bobsk);
     sodium_bin2hex(hex, sizeof hex, bobpk, sizeof bobpk);

test/default/scalarmult5.c

@@ -19,7 +19,6 @@ main(void)
 {
     unsigned char k[32];
     char          hex[65];
-    int           i;
     int           ret;
 
     ret = crypto_scalarmult(k, alicesk, bobpk);