IO::Generic#wait: fix call to Wrapper#wait_any (#76)

lib/async/io/generic.rb

@@ -169,7 +169,7 @@ def wait(timeout = self.timeout, mode = :read)
 				when :write
 					wait_writable(timeout)
 				else
-					wait_any(:rw, timeout)
+					wait_any(timeout)
 				end
 			rescue TimeoutError
 				return nil

spec/async/io/generic_spec.rb

@@ -70,6 +70,32 @@
 
 			[reader, writer].each(&:wait)
 		end
+
+    it "can wait for anything" do
+			reader = reactor.async do |task|
+				duration = Async::Clock.measure do
+					input.wait(1, nil)
+				end
+
+				expect(duration).to be >= wait_duration
+				expect(input.read(1024)).to be == message
+
+				input.close
+			end
+
+			writer = reactor.async do |task|
+				duration = Async::Clock.measure do
+					output.wait(1, :write)
+				end
+
+				task.sleep(wait_duration)
+
+				output.write(message)
+				output.close
+			end
+
+			[reader, writer].each(&:wait)
+    end
 
 		it "can return nil when timeout is exceeded" do
 			reader = reactor.async do |task|