Changed Ubuntu 14.04 kernel to xenial

Change-Id: Ic658be2ac237f5326bdec776eb9c91c946f18acf
diff --git a/ubuntu-14.04/scripts/base.sh b/ubuntu-14.04/scripts/base.sh
index 83f1a98..df8a8fe 100644
--- a/ubuntu-14.04/scripts/base.sh
+++ b/ubuntu-14.04/scripts/base.sh
@@ -15,7 +15,7 @@
 # Cleanup old kernels, ensure latest is installed via virtual package
 apt-get purge -y linux-image-* linux-headers-*
 if [ ! -f /tmp/no_install_kernel ]; then
-    apt-get install -y linux-generic-lts-vivid
+    apt-get install -y linux-generic-lts-xenial
 
     # Update grub cmdline
     sed -i 's|GRUB_CMDLINE_LINUX_DEFAULT=.*|GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"|g' /etc/default/grub