Use os.execv instead of subprocess.run when no further action is taken.

This prevents the underlying file from being marked busy while a
long-running action is happening (e.g. eureka is open).

dcc/rib.py

@@ -1,7 +1,6 @@
 import dcc.doom_base
 import pathlib
 import os
-import subprocess
 import time
 
 
@@ -42,7 +41,7 @@ class RIB(dcc.doom_base.WadMap):
                 + f"and map {parsed_args.map} (tried to look in {demodir})"
             )
 
-        subprocess.run(
+        os.execv(self.dsda,
             [self.dsda] + self.dsda_preamble(warp=False)
             + ["-playdemo", demo]
             + ["-skiptic", str(-35 * parsed_args.secs_before)]