[GAME] S.L.A.M doesn't detonate despite the detonator is armed if the right hand holds a tripmine ready to be attached

[Vlad-Melnichuk]

Hello, I wish to contribute the fix for the SLAM bug that has been around for 17 years since HL2DM.

Steps to reproduce:

1. Throw a SLAM, as a result, the left hand holds the armed detonator.
2. Face a surface point blank, so that the right hand holds a tripmine ready to attach.
3. Click secondary attack (detonation).

Observed behavior: nothing happens.

Expected behavior: the thrown SLAM should detonate
https://youtu.be/pvfdsDBldqI?feature=shared

Here's a pull request to Valve repo with my change only (I had only one GitHub account back in the day, created this one for HL2 modding and kept that one for Doom) ValveSoftware#532

I also found a commit across GitHub SDK2013 forks that included my fix as well as about a dozen other ones. FIREFIGHT-RELOADED/FIREFIGHT-RELOADED-src-sdk-2013@b613544