heatlhchecks are failing due to no_proxy use of CIDR notation

Issue

• When configuring proxy in /etc/environment and using CIDR notation in no_proxy, heatlhchecks are failing on the undercloud. Proxy configuration on the undercloud is documented here.

• The following errors are seen in /var/log/messages:

Apr 27 14:29:45 undercloud healthcheck_glance_api[895384]: curl: (22) The requested URL returned error: 407 Proxy Authentication Required
Apr 27 14:29:45 undercloud healthcheck_glance_api[895384]: 407 10.10.10.10:8080 0.069699 seconds
Apr 27 14:29:45 undercloud healthcheck_glance_api[895384]: Error: non zero exit code: 1: OCI runtime error
Apr 27 14:29:45 undercloud systemd[1]: tripleo_glance_api_healthcheck.service: Main process exited, code=exited, status=1/FAILURE
Apr 27 14:29:45 undercloud systemd[1]: tripleo_glance_api_healthcheck.service: Failed with result 'exit-code'.