debian: add /snap/bin to the secure-path

[mvo5]

LP: #1595558

[zyga]

Looks good. Thank you!

[mvo5]

Jamie prefer to modify it directly in sudo instead:

mvo: as for setting it at all, I'm not thrilled about adding it to root's secure_path, no, but I'm not sure there is a choice. if we are doing it, I think I prefer /etc/sudoers is modified for Ubuntu

[jdstrand]

For posterity, here was the reasoning:

"10:55 < jdstrand> because for 12 years people know to look in /etc/sudoers to adjust secure_path if they need to. now they would adjust it only to have it overridden to what is in snapd. the two might go out of sync, etc
10:55 < jdstrand> for 15.04 we used ubuntu-core-config to adjust /etc/sudoers to include it last in the path
10:56 < jdstrand> the PR also doesn't consider that other distros may not set secure_path or that they may have a different one than Ubuntu
10:57 < jdstrand> mvo: as for setting it at all, I'm not thrilled about adding it to root's secure_path, no, but I'm not sure there is a choice. if we are doing it, I think I prefer /etc/sudoers is modified for Ubuntu
10:59 < tyhicks> jdstrand: I agree - modifying /etc/sudoers at the distro level is the better solution since the PR isn't appropriate for other distros"