SSL: simplified ssl_password_file error handling.

Instead of collecting a number of the possible SSL_CTX_use_PrivateKey_file()
error codes that becomes more and more difficult with the rising variety of
OpenSSL versions and its derivatives, just continue with the next password.

Multiple passwords in a single ssl_password_file feature was broken after
recent OpenSSL changes (commit 4aac102f75b517bdb56b1bcfd0a856052d559f6e).

Affected OpenSSL releases: 0.9.8zc, 1.0.0o, 1.0.1j and 1.0.2-beta3.

Reported by Piotr Sikora.

Author: pluknet

src/event/ngx_event_openssl.c

@@ -404,20 +404,9 @@ ngx_ssl_certificate(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *cert,
         }
 
         if (--tries) {
-            n = ERR_peek_error();
-
-#ifdef OPENSSL_IS_BORINGSSL
-            if (ERR_GET_LIB(n) == ERR_LIB_CIPHER
-                && ERR_GET_REASON(n) == CIPHER_R_BAD_DECRYPT)
-#else
-            if (ERR_GET_LIB(n) == ERR_LIB_EVP
-                && ERR_GET_REASON(n) == EVP_R_BAD_DECRYPT)
-#endif
-            {
-                ERR_clear_error();
-                SSL_CTX_set_default_passwd_cb_userdata(ssl->ctx, ++pwd);
-                continue;
-            }
+            ERR_clear_error();
+            SSL_CTX_set_default_passwd_cb_userdata(ssl->ctx, ++pwd);
+            continue;
         }
 
         ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,