Update usage of linux blink try bot to use linux_trusty_blink_rel.

Reason: We're planning to drop support for Linux Precise for layout tests.

BUG=chromium:660580
NOTRY=true

Review-Url: https://codereview.chromium.org/2475563002
Cr-Commit-Position: refs/heads/master@{#40717}

tools/release/auto_roll.py

@@ -20,7 +20,7 @@ Please close rolling in case of a roll revert:
 https://v8-roll.appspot.com/
 This only works with a Google account.
 
-CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel""")
+CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel""")
 
 class Preparation(Step):
   MESSAGE = "Preparation."

tools/release/test_scripts.py

@@ -1044,7 +1044,7 @@ Please close rolling in case of a roll revert:
 https://v8-roll.appspot.com/
 This only works with a Google account.
 
-CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
+CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
 
 TBR=reviewer@chromium.org"""