gpgme_ctx_set_engine_info added as a new interface

[keitaroemotion]

Currently, ruby-gpgme's set_info contaminates the global gpg status. For example, if there are several gpg process running simultaneously, one gpg fails since the other deprives of the working repository.

Then I added a new interface called set_info_safe, which take context as an argument so that it does not harm the other gpg related processes.

[coveralls]

Coverage decreased (-0.2%) to 90.261% when pulling ef9f1d7 on keitaroemotion:add-non-intrusive-set-info into f70d026 on ueno:master.

[iwat]

Why don't you put that method to GPGME::Ctx class?

However, I'm surprised that gpgme_set_engine_info is already exposed.

[keitaroemotion]

@chaiwat You're right. now it has been moved into Ctx na. Yes.... so maybe initially people tried to implemented it but turned out to be it was forgotten to implement... I assume....

[coveralls]

Coverage decreased (-0.2%) to 90.261% when pulling be9e87b on keitaroemotion:add-non-intrusive-set-info into f70d026 on ueno:master.

[keitaroemotion]

@ueno Please merge this branch 🙇 お願いします

[djberg96]

Would recommend changing the name to set_engine_info. I don't think you need 'safely', it's understood to be happening at the context level since it's a context object.