Fix NPE in WebView relro creator process.

There's no context available in the relro creator process, resulting in
a NPE and crash when it tries to see if WebView is supported. Skip the
check in this case, because we know it's supported if we ran the relro
creation process at all.

Change-Id: I95e9aad7407b8f73dddf8a8b685d41d2f500736a
Fixes: 67398770
Test: boot, make sure no crash dialog from "android"