bootctrl HAL 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: builds; verify HAL still works

In support of b/33844934

Change-Id: Iba190c717cf02d2dfe90b470f82b6ca4a82b6c07
Merged-In: Idc2c5ba09f2486ff9cc9815d72a7e5a0af323b22
diff --git a/bootctl/bootctl.cpp b/bootctl/bootctl.cpp
index 5f8b979..2b3865e 100644
--- a/bootctl/bootctl.cpp
+++ b/bootctl/bootctl.cpp
@@ -184,7 +184,7 @@
         return EX_USAGE;
     }
 
-    module = IBootControl::getService("bootctrl");
+    module = IBootControl::getService();
     if (module == NULL) {
         fprintf(stderr, "Error getting bootctrl module.\n");
         return EX_SOFTWARE;