cleanup top level builddir before build

[smuzaffar]

No description provided.

[cmsbuild]

A new Pull Request was created by @smuzaffar for branch V00-34-XX.

@akritkbehera, @cmsbuild, @iarspider, @raoatifshad, @smuzaffar can you please review it and eventually sign? Thanks.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.
cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[smuzaffar]

+externals

tests passed via #210

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next V00-34-XX IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @ftenchini, @mandrenguyen, @sextonkennedy (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

Pull request #240 was updated.

[smuzaffar]

+externals

tests passed via #210

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next V00-34-XX IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @sextonkennedy, @ftenchini, @mandrenguyen (and backports should be raised in the release meeting by the corresponding L2)