Locking DUT for now

https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/hosts/chromeos2-row1-rack8-host1/907681-provision/20182105201635/crashinfo.chromeos2-row1-rack8-host1/

<6>[    1.447824] device-mapper: init: dm-0 is ready
<3>[    1.449524] EXT4-fs (dm-0): VFS: Found ext4 filesystem with invalid superblock checksum.  Run e2fsck?
<5>[    1.449557] VFS: Cannot open root device "dm-0" or unknown-block(254,0): error -74
<5>[    1.449564] Please append a correct "root=" boot option; here are the available partitions:
<5>[    1.449573] 0800       125034840 sda  driver: sd
<5>[    1.449581]   0801       120682496 sda1 3621cfa2-49f1-ec45-821a-71217a7cba88
<5>[    1.449589]   0802           16384 sda2 af05cd96-4bf5-9e42-9e09-9d96777fbef9
<5>[    1.449597]   0803         2097152 sda3 b618df20-f06d-3347-aa2f-a152b1f998b6
<5>[    1.449604]   0804           16384 sda4 5c7752d9-61fa-9745-8009-9eaf80833444
<5>[    1.449612]   0805         2097152 sda5 b1abdc6c-dab7-a045-b7a4-77ba5a6f70ca
<5>[    1.449619]   0806               0 sda6 b0ad6deb-9d85-6f4f-9da4-11265837b917
<5>[    1.449627]   0807               0 sda7 1fb12203-8138-be47-bf82-1fb1bd859aea
<5>[    1.449634]   0808           16384 sda8 f6b96b96-4208-214c-97c2-9d903289f3a2
<5>[    1.449642]   0809               0 sda9 75ebb8d9-4992-8e4e-b8c3-8fe8646c3ca5
<5>[    1.449649]   080a               0 sda10 3da36b85-f0ab-1a4a-a231-bb6f247ebca3
<5>[    1.449657]   080b            8192 sda11 5ad73299-d8e9-d843-a814-df7606af1329
<5>[    1.449665]   080c           32768 sda12 7a3d3e24-ac12-f941-bc4b-d0315264510e
<5>[    1.449673] fe00         2048000 dm-0  (driver?)
<0>[    1.449679] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(254,0)
<5>[    1.449688] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0 #1
<5>[    1.449694] Hardware name: GOOGLE Guado, BIOS Google_Guado.6301.108.4 04/01/2015
<5>[    1.449701]  0000000000000000 00000000639644a7 ffff880468681de8 ffffffff864d566f
<5>[    1.449711]  ffffffff8676979d ffff880468681e70 ffffffff864d4f91 6566002000000010
<5>[    1.449721]  ffff880468681e80 ffff880468681e18 00000000639644a7 0000000000000008
<5>[    1.449731] Call Trace:
<5>[    1.449740]  [<ffffffff864d566f>] dump_stack+0x4d/0x6f
<5>[    1.449746]  [<ffffffff864d4f91>] panic+0xcf/0x1e2
<5>[    1.449754]  [<ffffffff86b063ad>] mount_block_root+0x294/0x2a3
<5>[    1.449761]  [<ffffffff86b0640f>] mount_root+0x53/0x56
<5>[    1.449768]  [<ffffffff86b0654e>] prepare_namespace+0x13c/0x174
<5>[    1.449775]  [<ffffffff86b0602b>] kernel_init_freeable+0x20e/0x232
<5>[    1.449784]  [<ffffffff864d1d1e>] ? rest_init+0x82/0x82
<5>[    1.449791]  [<ffffffff864d1d2c>] kernel_init+0xe/0xda
<5>[    1.449798]  [<ffffffff864dad2c>] ret_from_fork+0x7c/0xb0
<5>[    1.449806]  [<ffffffff864d1d1e>] ? rest_init+0x82/0x82
<0>[