sdk/create: drop gnupg env vars from env_keep
We don't want to carry these with us when entering the SDK.
@@ -69,7 +69,7 @@ COREOS_BUILD_ID COREOS_OFFICIAL \
EMAIL GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME \
GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME \
GIT_PROXY_COMMAND GIT_SSH RSYNC_PROXY \
-GNUPGHOME GPG_AGENT_INFO SSH_AUTH_SOCK \
+SSH_AUTH_SOCK \
BOTO_PATH GOOGLE_APPLICATION_CREDENTIALS \
USE FEATURES PORTAGE_USERNAME \
all_proxy ftp_proxy http_proxy https_proxy no_proxy"
