Add missing defines/cases for RSA_PSK key exchange
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 3cde375..53ed937 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1988,6 +1988,7 @@
     SSL_DEBUG_MSG( 2, ( "=> write certificate verify" ) );
 
     if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
         ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ||
         ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
     {
@@ -2013,6 +2014,7 @@
     SSL_DEBUG_MSG( 2, ( "=> write certificate verify" ) );
 
     if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
         ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ||
         ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
     {