Initialize variable ck_interface with NULL

[fschueller-ifd]

Description

Some pkcs11-libs cause memory-problems if the variable passed is not initialized.

Checklist

• Code modified for feature

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• This feature/change has adequate documentation added
• Code conform to coding style that today cannot yet be enforced via the check style test
• Commits have short titles and sensible commit messages

[Jakuje]

I think the code comment you wrote should be in commit message. Otherwise looks good

[fschueller-ifd]

I think the code comment you wrote should be in commit message. Otherwise looks good

Sorry for that, actually I tried to C&P teh comment into the commit, but there where to many new interfaces an external obstacles in the way of getting the easy fix into github...

[simo5]

yup, please drop the comment which will make the style check failure go away as well.

[simo5]

@fschueller-ifd if you do not know how to amend the commit let me know and I'll do it for you before merging.