Remove previous wheels before creating a new one.

[VJalili]

Since there can be wheels belonging to different version of pulsar already existing in that folder, and since that can cause issues for building docker image as it uses *, hence it would be better to empty the folder of any previous wheels first.

[coveralls]

Coverage increased (+0.03%) to 80.711% when pulling 6723f8d on VJalili:patch-1 into ddf2fde on galaxyproject:master.

[coveralls]

Coverage increased (+0.03%) to 80.711% when pulling 6723f8d on VJalili:patch-1 into ddf2fde on galaxyproject:master.

[jmchilton]

Encountered the same thing, but fixed it by including deleting the wheel in the make dist rule -> make clean.

[VJalili]

@jmchilton both methods seem reasonable to me; we can implement whichever you prefer.

[bgruening]

@VJalili make clean seems to me better.