Backport of api-gateway: Fix nil pointer exception panic into release/1.2.x#2493

sarahalsmiller merged 4 commits into

release/1.2.xhashicorp/consul-k8s:release/1.2.xfrom

backport/bug/nil-pointer-request-header-modifier/possibly-united-shadhashicorp/consul-k8s:backport/bug/nil-pointer-request-header-modifier/possibly-united-shadCopy head branch name to clipboard