startkde: Avoid pushing shell variables to UpdateLaunchEnvJob

Currently, startplasma filters out shell variables when loading env scripts and systemd environment variables. However, this is insufficient if startplasma itself was run from within a shell, which is the case with X11 sessions in some distros. This causes SHELL=/bin/bash to be set in applications' launch environments, which may cause unexpected behavior. One of the most visible examples is Konsole, where the default profile will load bash (due to $SHELL) instead of the user's actual shell.

This commit adds an additional check to filter out shell variables before they are sent to UpdateLaunchEnvJob.

Signed-off-by: Andrew Gunnerson chillermillerlong@hotmail.com

(cherry picked from commit 410374e9)