base: make CAP session upgradeable

* Introduce 'Out_of_metadata' exception for capability allocation

Ref #1443

repos/base-linux/src/core/include/cap_session_component.h

@@ -36,6 +36,8 @@ namespace Genode {
 
 			Cap_session_component(Allocator *md_alloc, const char *args) {}
 
+			void upgrade_ram_quota(size_t ram_quota) { }
+
 			Native_capability alloc(Native_capability ep)
 			{
 				Lock::Guard lock_guard(_lock());