Remove enum elaborated type specifier

...from orientation params. Elaborated type specifiers are not needed
for C++ code and removing them makes doxygen happy. Verified working
on both gcc2h and gcc4h builds.

headers/os/interface/GroupView.h

@@ -13,10 +13,10 @@
 class BGroupView : public BView {
 public:
 								BGroupView(
-									enum orientation orientation = B_HORIZONTAL,
+									orientation orientation = B_HORIZONTAL,
 									float spacing = B_USE_DEFAULT_SPACING);
 								BGroupView(const char* name,
-									enum orientation orientation = B_HORIZONTAL,
+									orientation orientation = B_HORIZONTAL,
 									float spacing = B_USE_DEFAULT_SPACING);
 								BGroupView(BMessage* from);
 	virtual						~BGroupView();