Add boot_once support to bootool

From: Ryan Stutsman <stutsman@google.com>
Signed-off-by: Martin J. Bligh <mbligh@google.com>

The INSTALL file from upstream specifies a way to generate a
monolithic script for boottool.  Attached is such a monolithic version
of the upstream boottool (client/tools/boottool).  This new version
adds support for boot-once in GRUB.

The following patch makes it so that kernels installed by autotest are
boot-once by default. 



git-svn-id: http://test.kernel.org/svn/autotest/trunk@568 592f7852-d20e-0410-864c-8624ca9c26a4
diff --git a/client/bin/kernel.py b/client/bin/kernel.py
index c75947f..2d10651 100755
--- a/client/bin/kernel.py
+++ b/client/bin/kernel.py
@@ -384,14 +384,16 @@
 			return arch
 
 
-	def boot(self, args=''):
+	def boot(self, args='', once=True):
 		""" install and boot this kernel, do not care how
 		    just make it happen.
 		"""
 
 		# Install this kernel.
 		self.install()
-		self.add_to_bootloader(args=args)
+		self.add_to_bootloader(args=args, tag='autotest')
+		if once:
+			self.job.bootloader.boot_once('autotest')
 
 		# Boot it.
 		self.job.reboot()