cmdlib: don't use cache qcow for composes; use virtiofs

Now that our OSBuild workflow is using the cache we saw at least one
case where the pipeline was running out of space. Since we had a
previous proposal [1] to just drop the cahce altogether anyway let's
try to at least remove it from the runcompose functions to eliminate
the use of it there anyway.

[1] #3615

src/cmdlib.sh

@@ -563,7 +563,7 @@ runcompose_tree() {
         (umask 0022 && sudo -E "$@")
         sudo chown -R -h "${USER}":"${USER}" "${tmprepo}"
     else
-        runvm_with_cache -- "$@" --repo "${repo}" --write-composejson-to "${composejson}"
+        runvm -- "$@" --repo "${repo}" --write-composejson-to "${composejson}"
     fi
 }
 
@@ -587,7 +587,7 @@ runcompose_extensions() {
         (umask 0022 && sudo -E "$@")
         sudo chown -R -h "${USER}":"${USER}" "${outputdir}"
     else
-        runvm_with_cache -- "$@"
+        runvm -- "$@"
     fi
 }