Fix disclosure date

## Verification steps

### Pre-fix:

- [ ] Run `tools/msftidy.rb modules/auxiliary/scanner/http/oracle_demantra_database_credentials_leak.rb`
- [ ] See the error: `[ERROR] Incorrect disclosure date format`

### Post-fix:

- [ ] Run `tools/msftidy.rb modules/auxiliary/scanner/http/oracle_demantra_database_credentials_leak.rb`
- [ ] See no error.

### Avoiding this in the future:

- [ ] Read the comment docs on [pre-commit-hook](https://github.com/rapid7/metasploit-framework/blob/master/tools/dev/pre-commit-hook.rb)
- [ ] Type `ln -sf ../../tools/dev/pre-commit-hook.rb .git/hooks/pre-commit` to catch errors before commits
- [ ] Type `ln -sf ../../tools/dev/pre-commit-hook.rb .git/hooks/post-merge` to catch errors after merge.

@jvazquez-r7 and @0x3fcoma, take note, since this came from #3197. How do I know? Behold:

````
$ git branch -r --contains $(git log --oneline modules/auxiliary/scanner/http/oracle_demantra_database_credentials_leak.rb | tail -1 | cut -f 1 -d " ") | grep pr
  upstream/pr/3197
````