Increase the bus factor for WebSQL OWNERS.

BUG=

Change-Id: I3f2e1c8b292777e454b5bc641dbe684929ead2a3
Reviewed-on: https://chromium-review.googlesource.com/576808Reviewed-by: Michael Nordman <michaeln@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488527}

third_party/WebKit/Source/modules/webdatabase/OWNERS

+# Primary
 michaeln@chromium.org
 
+# Seconday
+pwnall@chromium.org
+jsbell@chromium.org
+
 # TEAM: storage-dev@chromium.org
 # COMPONENT: Blink>Storage