fix:  Fix stupid memory leak. (#1005)

Pointed out by @oleh-yudin-ring.  Follow-up to #996.
diff --git a/src/iperf_auth.c b/src/iperf_auth.c
index fde44a6..46211e0 100644
--- a/src/iperf_auth.c
+++ b/src/iperf_auth.c
@@ -294,6 +294,7 @@
     unsigned char *encrypted = NULL;
     int encrypted_len;
     encrypted_len = encrypt_rsa_message(text, public_key, &encrypted);
+    free(text);
     if (encrypted_len < 0) {
       return -1;
     }