[Oracle-Comp] support read enviroment variable NLS_DATE_FORMAT

[raywill]

Sqlplus enables the user setting NLS_DATE_FORMAT in bashrc/bash_profile.

When connecting to database server, sqlplus read NLS_DATE_FORMAT as environment variable and set it to database server.

For some company, they depend on this behavior. We can support this feature.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: raywill
:x: 晓楚

---

晓楚 seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}