[autotest] Update cros stable version.

R46 was deleted from Google Storage. Using the new default from
atest.

BUG=chromium:591965
TEST=None

Change-Id: If7803ba3721fc314f908ac73336327d2fadaf605
Reviewed-on: https://chromium-review.googlesource.com/330426
Tested-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
diff --git a/global_config.ini b/global_config.ini
index 7589b91..c4d6153 100644
--- a/global_config.ini
+++ b/global_config.ini
@@ -241,7 +241,7 @@
 # Use `cli/atest stable_version` command to view or manage stable versions.
 # WARNING! Edit following setting will NOT work if stable versions are stored
 # in afe_stable_versions table already!
-stable_cros_version: R46-7390.59.0
+stable_cros_version: R49-7834.42.0
 stable_build_pattern: %s-release/%s
 source_tree: /usr/local/google/chromeos
 gs_offloading_enabled: True