CXX-277 Eliminate unused variable

Author: acmorrow

src/mongo/client/examples/authTest.cpp

@@ -93,7 +93,7 @@ int main( int argc, const char **argv ) {
         // Shouldn't get here.
         cout << "Authentication with invalid password should have failed but didn't" << endl;
         return EXIT_FAILURE;
-    } catch (const DBException& e) {
+    } catch (const DBException&) {
         // expected
     }
     return EXIT_SUCCESS;

src/mongo/client/examples/clientTest.cpp

@@ -180,7 +180,7 @@ int main( int argc, const char **argv ) {
         // upsert
         try {
             conn.update( ns , BSONObjBuilder().append( "name" , "eliot2" ).obj() , after , UpdateOption_Upsert );
-        } catch (OperationException& oe) {
+        } catch (OperationException&) {
             // This upsert throws an OperationException because of a duplicate key error:
             // The upserted document has the same _id as one already in the collection
         }

src/mongo/client/examples/simple_client_demo.cpp

@@ -62,7 +62,7 @@ int main(int argc, char* argv[]) {
 
         try {
             c.insert("test.foo", o); // will cause a dup key error on "hello" field
-        } catch (const OperationException &oe) {
+        } catch (const OperationException &) {
             // duplicate key error
         }
         cout << "we expect a dup key error here:" << endl;