fix authentication-tests-darwinssl (#1400)

* silence `kinit` check

* do not assume existence of `krb5.conf`

Instead: check for presence of `kinit` command.
`/etc/krb5.conf` does not appear present on macOS hosts.

* regenerate Evergreen config

Author: kevinAlbs

.evergreen/config_generator/components/funcs/prepare_kerberos.py

@@ -12,7 +12,7 @@ class PrepareKerberos(Function):
             working_dir='mongoc',
             silent=True,
             script='''\
-            if test "${keytab|}" && [[ -f /etc/krb5.conf ]]; then
+            if test "${keytab|}" && command -v kinit >/dev/null; then
                 echo "${keytab}" > /tmp/drivers.keytab.base64
                 base64 --decode /tmp/drivers.keytab.base64 > /tmp/drivers.keytab
                 if touch /etc/krb5.conf 2>/dev/null; then

.evergreen/generated_configs/functions.yml

@@ -259,7 +259,7 @@ functions:
         args:
           - -c
           - |
-            if test "${keytab|}" && [[ -f /etc/krb5.conf ]]; then
+            if test "${keytab|}" && command -v kinit >/dev/null; then
                 echo "${keytab}" > /tmp/drivers.keytab.base64
                 base64 --decode /tmp/drivers.keytab.base64 > /tmp/drivers.keytab
                 if touch /etc/krb5.conf 2>/dev/null; then

.evergreen/scripts/run-auth-tests.sh

@@ -62,7 +62,7 @@ esac
 : "${test_gssapi:?}"
 : "${ip_addr:?}"
 
-if command -v kinit && [[ -f /tmp/drivers.keytab ]]; then
+if command -v kinit >/dev/null && [[ -f /tmp/drivers.keytab ]]; then
   kinit -k -t /tmp/drivers.keytab -p [email protected] || true
 fi