database: run triggers with r*id = e*id
The 'apk' utility is intended to run as root, however it is not strictly necessary depending on the tasks it needs to execute.
If invoked as euid 0 but ruid something else, the mismatch is detected by the (shell) interpreter, which sets euid to ruid, which can cause a trigger expecting privileges to fail silently.
Fixes: horizon#379 (closed)