CA file parameter should be configurable

The CA file should not be set by the absolute path that may not exist on
the system. If `CA_FILE` parameter is present in `~/.awscred`, it will
be used. Otherwise, `/etc/pki/tls/certs/ca-bundle.trust.crt`, or the
system default CA file will be used.
Parseconfig is old on CI
Fix key for AWS config hash
Merge pull request #67 from BanzaiMan/configurable_ca_file

Merged by openshift-bot