GUACAMOLE-221: Clean up VNC mutex; update comments.

src/protocols/rdp/client.c

@@ -226,6 +226,7 @@ int guac_rdp_client_free_handler(guac_client* client) {
     
     /* Destroy the pthread conditional handler */
     pthread_cond_destroy(&(rdp_client->rdp_credential_cond));
+    pthread_mutex_destroy(&(rdp_client->rdp_credential_lock));
 
     pthread_rwlock_destroy(&(rdp_client->lock));
 

src/protocols/rdp/rdp.h

@@ -184,6 +184,10 @@ typedef struct guac_rdp_client {
     /**
      * Flags for tracking events related to the rdp_credential_cond
      * pthread condition.
+     * 
+     * @see GUAC_RDP_CRED_FLAG_USERNAME
+     * @see GUAC_RDP_CRED_FLAG_PASSWORD
+     * @see GUAC_RDP_CRED_FLAG_DOMAIN
      */
     unsigned rdp_credential_flags;
 

src/protocols/vnc/vnc.h

@@ -159,6 +159,9 @@ typedef struct guac_vnc_client {
     /**
      * A field to track flags related to retrieving required credentials
      * from the client.
+     *
+     * @see GUAC_VNC_COND_FLAG_USERNAME
+     * @see GUAC_VNC_COND_FLAG_PASSWORD
      */
     unsigned vnc_credential_flags;