Give a better name to STOP_REASON_ERROR

It indicates crosvm failed to start the VM, so
STOP_REASON_START_FAILED.

Slightly gratuitously I also renamed the internal DeathReason - mainly
because this is just a much clearer name.

I didn't change the statslog version, because that would just be too
complicated.

Bug: 261037705
Test: atest MicrodroidTests
Change-Id: I5effdba86ea49ff919d82810926fb14ccbbd8499
diff --git a/virtualizationservice/src/atom.rs b/virtualizationservice/src/atom.rs
index 9c74d1e..85e37af 100644
--- a/virtualizationservice/src/atom.rs
+++ b/virtualizationservice/src/atom.rs
@@ -182,7 +182,7 @@
                 DeathReason::KILLED => vm_exited::DeathReason::Killed,
                 DeathReason::UNKNOWN => vm_exited::DeathReason::Unknown,
                 DeathReason::SHUTDOWN => vm_exited::DeathReason::Shutdown,
-                DeathReason::ERROR => vm_exited::DeathReason::Error,
+                DeathReason::START_FAILED => vm_exited::DeathReason::Error,
                 DeathReason::REBOOT => vm_exited::DeathReason::Reboot,
                 DeathReason::CRASH => vm_exited::DeathReason::Crash,
                 DeathReason::PVM_FIRMWARE_PUBLIC_KEY_MISMATCH => {
diff --git a/virtualizationservice/src/crosvm.rs b/virtualizationservice/src/crosvm.rs
index 0fdc293..406054c 100644
--- a/virtualizationservice/src/crosvm.rs
+++ b/virtualizationservice/src/crosvm.rs
@@ -62,7 +62,7 @@
 const CROSVM_PLATFORM_VERSION: &str = "1.0.0";
 
 /// The exit status which crosvm returns when it has an error starting a VM.
-const CROSVM_ERROR_STATUS: i32 = 1;
+const CROSVM_START_ERROR_STATUS: i32 = 1;
 /// The exit status which crosvm returns when a VM requests a reboot.
 const CROSVM_REBOOT_STATUS: i32 = 32;
 /// The exit status which crosvm returns when it crashes due to an error.
@@ -637,7 +637,7 @@
         match status.code() {
             None => DeathReason::KILLED,
             Some(0) => DeathReason::SHUTDOWN,
-            Some(CROSVM_ERROR_STATUS) => DeathReason::ERROR,
+            Some(CROSVM_START_ERROR_STATUS) => DeathReason::START_FAILED,
             Some(CROSVM_REBOOT_STATUS) => DeathReason::REBOOT,
             Some(CROSVM_CRASH_STATUS) => DeathReason::CRASH,
             Some(CROSVM_WATCHDOG_REBOOT_STATUS) => DeathReason::WATCHDOG_REBOOT,