nova: early message on successful boot

This patch fixes a regression with run/log_core introduced by

  2064ffd64b nova: support multidimensional affinity space

The run tool uses a log message 'run_boot_string' to detect successful
boot as well as to detect unexpected reboots. This message should never
be logged twice and, thus, should not be part of the core_log. The patch
mentioned above moved the former run_boot_string after the core_log
initialization.

tool/run/boot_dir/nova

@@ -6,7 +6,7 @@ proc kernel_files { } { return hypervisor }
 proc kernel_output { } { return "novga serial" }
 
 proc run_boot_string { } {
-	return "\nHypervisor reports "
+	return "\nHypervisor NOVA "
 }
 
 proc apply_microcode { } { return false }