IServiceManager/ITokenManager uses "default" service name

The getService() and registerAsService() methods of interface objects
now have default parameters of "default" for the service name. HALs
will not have to use any service name unless they want to register
more than one service.

Test: boots
Test: hidl_test

Bug: 33844934
Change-Id: I0938f9b5b6ab054eafc60b58fbe686a01124e71d
diff --git a/service.cpp b/service.cpp
index c18ce81..f20fb0e 100644
--- a/service.cpp
+++ b/service.cpp
@@ -43,7 +43,7 @@
 using android::hidl::manager::V1_0::implementation::ServiceManager;
 using android::hidl::token::V1_0::implementation::TokenManager;
 
-static std::string serviceName = "manager";
+static std::string serviceName = "default";
 
 class BinderCallback : public LooperCallback {
 public: