init: log all failures of Service::Start()

The move to returning Result from Service::Start() for better context
when starting process through init's builtins stops Service::Start()
failures from being logged from other contexts.  This change adds
those logs along with their context.

Test: boot bullhead, fail to start services via `setprop ctl.start`,
      see the expected error in dmesg

Change-Id: I45294f6abf00852f3d4c549a32eaf4920a51e6f0
diff --git a/init/init.cpp b/init/init.cpp
index e1bd3a2..4a8459f 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -177,7 +177,9 @@
 
         auto restart_time = s->time_started() + 5s;
         if (boot_clock::now() > restart_time) {
-            s->Start();
+            if (auto result = s->Start(); !result) {
+                LOG(ERROR) << "Could not restart process '" << s->name() << "': " << result.error();
+            }
         } else {
             if (!next_process_restart_time || restart_time < *next_process_restart_time) {
                 next_process_restart_time = restart_time;
@@ -195,7 +197,9 @@
     }
 
     if (msg == "start") {
-        svc->Start();
+        if (auto result = svc->Start(); !result) {
+            LOG(ERROR) << "Could not ctl.start service '" << name << "': " << result.error();
+        }
     } else if (msg == "stop") {
         svc->Stop();
     } else if (msg == "restart") {