VBox add Storage Volume support

* src/vbox/vbox_driver.c src/vbox/vbox_tmpl.c: adds the driver for
  storage volumes

src/vbox/vbox_driver.c

@@ -41,8 +41,10 @@
 
 extern virDriver vbox22Driver;
 extern virNetworkDriver vbox22NetworkDriver;
+extern virStorageDriver vbox22StorageDriver;
 extern virDriver vbox30Driver;
 extern virNetworkDriver vbox30NetworkDriver;
+extern virStorageDriver vbox30StorageDriver;
 
 static virDriver vboxDriverDummy;
 
@@ -55,6 +57,7 @@ static virDriver vboxDriverDummy;
 int vboxRegister(void) {
     virDriverPtr        driver;
     virNetworkDriverPtr networkDriver;
+    virStorageDriverPtr storageDriver;
     uint32_t            uVersion;
 
     /*
@@ -65,6 +68,7 @@ int vboxRegister(void) {
      */
     driver        = &vboxDriverDummy;
     networkDriver = &vbox22NetworkDriver;
+    storageDriver = &vbox22StorageDriver;
 
     /* Init the glue and get the API version. */
     if (VBoxCGlueInit() == 0) {
@@ -83,10 +87,12 @@ int vboxRegister(void) {
             DEBUG0("VirtualBox API version: 2.2");
             driver        = &vbox22Driver;
             networkDriver = &vbox22NetworkDriver;
+            storageDriver = &vbox22StorageDriver;
         } else if (uVersion >= 2002051 && uVersion < 3000051) {
             DEBUG0("VirtualBox API version: 3.0");
             driver        = &vbox30Driver;
             networkDriver = &vbox30NetworkDriver;
+            storageDriver = &vbox30StorageDriver;
         } else {
             DEBUG0("Unsupport VirtualBox API version");
         }
@@ -99,6 +105,8 @@ int vboxRegister(void) {
         return -1;
     if (virRegisterNetworkDriver(networkDriver) < 0)
         return -1;
+    if (virRegisterStorageDriver(storageDriver) < 0)
+        return -1;
 
     return 0;
 }