manylinux: clean the build directory before building wheels

[LucasGandel]

Commit #c953dc0 removed the clean step to allow accessing configured files when the script exists. However, when running two consecutive builds for different tarball specialization, the 1st build directory must be cleaned to make sure all libs are rebuilt for the right platform.

[LucasGandel]

@thewtex the change introduced in #200 breaks the ability to build multiple wheels with different "tarball specialization". When building the second wheel, there are some targets that are wrongly rebuilt with the previous specialization (see here).

This PR fixes it by cleaning any previous build before building a new wheel. Can you please review?

cc: @SimonRit

[thewtex]

@LucasGandel LGTM, thanks!

We are looking at updating the macOS XCode version, also. So, I will produce a new version with this change, in 5.3rc4.post3.

[LucasGandel]

We are looking at updating the macOS XCode version, also. So, I will produce a new version with this change, in 5.3rc4.post3.

Thanks a lot @thewtex!

[SimonRit]

Thanks a lot @thewtex . While waiting for 5.3rc4.post3, do you think it makes sense to restore the original linux asset for v5.3rc04.post2? My attempt at releasing RTK failed due to the faulty ITKPythonBuilds-linux.tar.zst , see here...