res_rtp_asterisk.c: Fix off nominal memory leak.

Change-Id: I95b1088d11244a2edae6607c12fbf33b38658a75

res/res_rtp_asterisk.c

@@ -1455,12 +1455,6 @@ static int ast_rtp_dtls_set_configuration(struct ast_rtp_instance *instance, con
 			return -1;
 		}
 
-		if (!(certbio = BIO_new(BIO_s_file()))) {
-			ast_log(LOG_ERROR, "Failed to allocate memory for certificate fingerprinting on RTP instance '%p'\n",
-				instance);
-			return -1;
-		}
-
 		if (rtp->local_hash == AST_RTP_DTLS_HASH_SHA1) {
 			type = EVP_sha1();
 		} else if (rtp->local_hash == AST_RTP_DTLS_HASH_SHA256) {
@@ -1471,6 +1465,12 @@ static int ast_rtp_dtls_set_configuration(struct ast_rtp_instance *instance, con
 			return -1;
 		}
 
+		if (!(certbio = BIO_new(BIO_s_file()))) {
+			ast_log(LOG_ERROR, "Failed to allocate memory for certificate fingerprinting on RTP instance '%p'\n",
+				instance);
+			return -1;
+		}
+
 		if (!BIO_read_filename(certbio, dtls_cfg->certfile) ||
 		    !(cert = PEM_read_bio_X509(certbio, NULL, 0, NULL)) ||
 		    !X509_digest(cert, type, fingerprint, &size) ||