init: add an initializer for keychord_id_

Add unit test to ensure all POD types of Service are initialized.

Bug: 37855222
Test: Ensure bugreport is triggered via keychord properly.
Test: New unit tests
Change-Id: If2cfea15a74ab417a7b909a60c264cb8eb990de7
diff --git a/init/service.cpp b/init/service.cpp
index 39f6709..3a9f622 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -158,6 +158,7 @@
       namespace_flags_(0),
       seclabel_(""),
       onrestart_(false, "<Service '" + name + "' onrestart>", 0),
+      keychord_id_(0),
       ioprio_class_(IoSchedClass_NONE),
       ioprio_pri_(0),
       priority_(0),
@@ -182,6 +183,7 @@
       namespace_flags_(namespace_flags),
       seclabel_(seclabel),
       onrestart_(false, "<Service '" + name + "' onrestart>", 0),
+      keychord_id_(0),
       ioprio_class_(IoSchedClass_NONE),
       ioprio_pri_(0),
       priority_(0),