Stop using deprecated function AServiceManager_getService()

AServiceManager_getService() is marked as deprecated and causes compiler
warnings when building vold.  It is deprecated because it waits for up
to 5 seconds for the service to become available, which is an arbitrary
amount.  Callers either want no wait (AServiceManager_checkService()) or
an indefinite wait (AServiceManager_waitForService()).  vold wants an
indefinite wait, so switch to using AServiceManager_waitForService().

Test: 'mmm system/vold' and verified that the warnings are gone
Test: Boot Cuttlefish
Flag: EXEMPT bugfix
Change-Id: Id9e9686f6d4ab8ef3beb23f4a85efb850dc8fece
diff --git a/Keystore.cpp b/Keystore.cpp
index adadde0..fd8a887 100644
--- a/Keystore.cpp
+++ b/Keystore.cpp
@@ -224,7 +224,7 @@
 }
 
 void Keystore::earlyBootEnded() {
-    ::ndk::SpAIBinder binder(AServiceManager_getService(maintenance_service_name));
+    ::ndk::SpAIBinder binder(AServiceManager_waitForService(maintenance_service_name));
     auto maint_service = ks2_maint::IKeystoreMaintenance::fromBinder(binder);
 
     if (!maint_service) {
@@ -237,7 +237,7 @@
 }
 
 void Keystore::deleteAllKeys() {
-    ::ndk::SpAIBinder binder(AServiceManager_getService(maintenance_service_name));
+    ::ndk::SpAIBinder binder(AServiceManager_waitForService(maintenance_service_name));
     auto maint_service = ks2_maint::IKeystoreMaintenance::fromBinder(binder);
 
     if (!maint_service) {