Fix DB#error and DB#last_status deprecation warnings in unit tests.

test/collection_test.rb

@@ -108,7 +108,7 @@ class TestCollection < Test::Unit::TestCase
     a = {"hello" => "world"}
     @@test.insert(a)
     @@test.insert(a)
-    assert(@@db.error.include?("E11000"))
+    assert(@@db.get_last_error.include?("E11000"))
 
     assert_raise OperationFailure do
       @@test.insert(a, :safe => true)

test/db_connection_test.rb

@@ -10,6 +10,6 @@ class DBConnectionTest < Test::Unit::TestCase
     db = Connection.new(host, port).db(MONGO_TEST_DB)
     coll = db.collection('test')
     coll.remove
-    db.error
+    db.get_last_error
   end
 end

test/db_test.rb

@@ -203,10 +203,10 @@ class DBTest < Test::Unit::TestCase
     @@db['test'].save("i" => 1)
 
     @@db['test'].update({"i" => 1}, {"$set" => {"i" => 2}})
-    assert @@db.last_status()["updatedExisting"]
+    assert @@db.get_last_error()["updatedExisting"]
 
     @@db['test'].update({"i" => 1}, {"$set" => {"i" => 500}})
-    assert !@@db.last_status()["updatedExisting"]
+    assert !@@db.get_last_error()["updatedExisting"]
   end
 
   def test_text_port_number_raises_no_errors

test/unit/db_test.rb

@@ -71,7 +71,7 @@ class DBTest < Test::Unit::TestCase
       should "raise an error if getlasterror fails" do
         @db.expects(:command).returns({})
         assert_raise Mongo::MongoDBError do
-          @db.error
+          @db.get_last_error
         end
       end