remove old extension file before building new php version

[henderkes]

What does this PR do?

I would like to integrate this into the LockFile somehow, but I'm not sure how.

please feel free to move it to the right location

[crazywhalecc]

Currently LockFile is only managing source and downloads, it's not managing buildroot.

How about deleting the module directory here only if it is detected that this build contains a shared extension?

[henderkes]

if it doesn't contain a shared extension, I don't think it's even created in the first place, so that would only add unnecessary code

[crazywhalecc]

At this point, it seems appropriate to delete it here.