Change log-level of Simple Chrome DEPS hooks from error to warning.

This increases verbosity by a single level. Practically, that just means
boards' SDKs that take a while to fetch will be printed. For example, it
will print statements like:
WARNING: It took 3m48.535s to fetch the SDK for amd64-generic. Consider removing it from your .gclient file if you no longer need to build for it.

Bug: 1034063
Change-Id: I7407bb503f4145e5de6d0e6d39b596a50ea46009
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2363314Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799280}

DEPS

@@ -4913,7 +4913,7 @@ hooks = [
       '--nogoma',
       '--nogn-gen',
       '--no-shell',
-      '--log-level=error',
+      '--log-level=warning',
       '--cache-dir=src/build/cros_cache/',
       '--use-external-config',
       '--boards={cros_boards_with_qemu_images}',
@@ -4931,7 +4931,7 @@ hooks = [
       '--nogoma',
       '--nogn-gen',
       '--no-shell',
-      '--log-level=error',
+      '--log-level=warning',
       '--cache-dir=src/build/cros_cache/',
       '--use-external-config',
       '--boards={cros_boards}',
@@ -4948,7 +4948,7 @@ hooks = [
       '--nogoma',
       '--nogn-gen',
       '--no-shell',
-      '--log-level=error',
+      '--log-level=warning',
       '--cache-dir=src/build/cros_cache/',
       '--boards={cros_boards_with_qemu_images}',
       '--download-vm',
@@ -4965,7 +4965,7 @@ hooks = [
       '--nogoma',
       '--nogn-gen',
       '--no-shell',
-      '--log-level=error',
+      '--log-level=warning',
       '--cache-dir=src/build/cros_cache/',
       '--boards={cros_boards}',
     ],