face: Rename all ChannelFactories to protocol Factories

Base class is ProtocolFactory and implementations are TcpFactory,
UnixStreamFactory, EthernetFactory.

Since Factories are doing more than just creating channels (some can
create faces directly), more general name is more appropriate.

Change-Id: I3d6c2460a1b29e244f8462453720f4e7785893ca
diff --git a/daemon/mgmt/manager-base.hpp b/daemon/mgmt/manager-base.hpp
index 8fb8cd3..78c6efe 100644
--- a/daemon/mgmt/manager-base.hpp
+++ b/daemon/mgmt/manager-base.hpp
@@ -19,6 +19,11 @@
 class ManagerBase
 {
 public:
+  struct Error : public std::runtime_error
+  {
+    Error(const std::string& what) : std::runtime_error(what) {}
+  };
+
   ManagerBase(shared_ptr<AppFace> face);
 
   virtual