AppServerLink: Switch to a recursive lock.

It seems in some applications (though not most of the ones I
initially tested) this can get used recursively, so we need
a recursive_lock in order to not deadlock.

Also commit a missed change from the previous commit.

headers/private/app/ServerLink.h

@@ -12,7 +12,6 @@
 
 
 #include <OS.h>
-#include <Locker.h>
 #include <LinkReceiver.h>
 #include <LinkSender.h>
 
@@ -34,7 +33,7 @@ class BGradient;
 
 namespace BPrivate {
 
-class ServerLink : public BLocker {
+class ServerLink {
 public:
 								ServerLink();
 	virtual						~ServerLink();