Don't delete ran-base at end of build

Subsequent pipelines can/might use the ran-base image. Further, before
building a new ran-base image, we delete it. Hence, it suffices to only
delete the image when necessary (before building a new one), and
otherwise leave the current (develop, ci-temp) ran-base image.

ci-scripts/cls_containerize.py

@@ -505,8 +505,6 @@ class Containerize():
 			cmd.run(f"{self.cli} image prune --force")
 
 		# Remove all intermediate build images and clean up
-		if self.ranAllowMerge and forceBaseImageBuild:
-			cmd.run(f"{self.cli} image rm {baseImage}:{baseTag}")
 		cmd.run(f"{self.cli} image rm ran-build:{imageTag} ran-build-asan:{imageTag}")
 		cmd.run(f"{self.cli} volume prune --force")