some port fixes

Author: erh

src/main/com/mongodb/DBPortPool.java

@@ -91,7 +91,6 @@ protected long memSize( DBPort p ){
 
     public DBPort get(){
 	DBPort port = null;
-	
 	if ( ! _waitingSem.tryAcquire() )
 	    throw new NoMoreConnection();
 

src/main/com/mongodb/DBTCPConnector.java

@@ -174,6 +174,7 @@ public Response call( DB db , DBCollection coll , OutMessage m , int retries )
 
         try {
             Response res = port.call( m , coll );
+            mp.done( port );
             ServerError err = res.getError();
 
             if ( err != null && err.isNotMasterError() ){
@@ -242,12 +243,18 @@ DBPort get( boolean keep ){
             if ( _port != null )
                 return _port;
 
-            DBPort p = _curPortPool.get();
-            if ( keep && _inRequest )
-                _port = p;
-            
-            _last = p;
-            return p;
+            try {
+                DBPort p = _curPortPool.get();
+                if ( keep && _inRequest )
+                    _port = p;
+                
+                _last = p;
+                return p;
+            }
+            catch ( DBPortPool.NoMoreConnection nmc ){
+                _internalStack = 0;
+                throw nmc;
+            }
         }
 
         void done( DBPort p ){