Clear the resolver timeout when setting default __res_params

This is currently a non-functional change, because base_timeout_msec is
never set to a non-default value (other than in unit tests).

Test: netd_unit_test --gtest_filter='ResolverTest.*'
Change-Id: I21989bab5cc9f55ee1392e30965eb405d720a28e
diff --git a/libc/dns/resolv/res_cache.c b/libc/dns/resolv/res_cache.c
index dda8694..d0673ef 100644
--- a/libc/dns/resolv/res_cache.c
+++ b/libc/dns/resolv/res_cache.c
@@ -1995,6 +1995,7 @@
     params->success_threshold = SUCCESS_THRESHOLD;
     params->min_samples = 0;
     params->max_samples = 0;
+    params->base_timeout_msec = 0;  // 0 = legacy algorithm
 }
 
 int