Enable dchecks on Mojo Linux FYI bot.

We only have one release bot for network service so far, so turn on dchecks there to get coverage. This avoids the optional trybot failing while the FYI bot is passing.

BUG=713857

Change-Id: I9fffe65c8cca6fb05994e9a88a42bd497f879ee1
Reviewed-on: https://chromium-review.googlesource.com/565188Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485401}

tools/mb/mb_config.pyl

@@ -205,7 +205,7 @@
       'Mac deterministic': 'release_bot_mac_strip',
       'Mac deterministic (dbg)': 'debug_bot',
       'Mojo ChromiumOS': 'chromeos_with_codecs_ozone_release_trybot',
-      'Mojo Linux': 'release_bot',
+      'Mojo Linux': 'release_trybot',
       'Mojo Windows': 'release_bot_x86_minimal_symbols',
       'Ozone Linux': 'release_bot_ozone_linux',
       'Site Isolation Android': 'android_release_bot_minimal_symbols_arm64',