Add missing DevSdkIgnoreRule rule variable

DevSdkIgnoreRule.IgnoreUpTo() will not work as expected without
the rule defined.

Bug: 184750836
Test: atest android.net.Ikev2VpnProfileTest#\
      testBuildExcludeLocalRoutesSet works as expected with ignore
      rule
Change-Id: I03a5b28963cd6feebe4358d57c070d941cd114e5
1 file changed