[Libguestfs] [PATCH v2] dib: handle unsetting functions in environment

[John Eckersberg]

When I turned off debug and actually looked at the normal output, this
is a bit noisy...

[jeckersb at baozi libguestfs]$ ./run virt-dib -B ~/git/diskimage-builder/lib/ --element-path ~/git/diskimage-builder/elements/ fedora-minimal
[   0.0] Elements: base fedora-minimal
[   0.0] Expanded elements: base dib-init-system dib-run-parts fedora-minimal install-types package-installs pkg-map redhat-common rpm-distro yum yum-minimal
[   0.0] Carried environment variables:
[   0.0] Preparing auxiliary data
[   0.2] Running: extra-data.d/10-create-pkg-map-dir
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_module()': not a valid identifier
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_scl()': not a valid identifier
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_module()': not a valid identifier
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_scl()': not a valid identifier
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_module()': not a valid identifier
/tmp/dib.dQ8W3Z/aux/fake-bin/sudo: line 39: unset: `BASH_FUNC_scl()': not a valid identifier
[   0.2] Running: extra-data.d/50-store-build-settings
[   0.2] Running: extra-data.d/99-enable-install-types
[   0.2] Running: extra-data.d/99-squash-package-install
[   0.3] Running: extra-data.d/99-yum-repo-conf
[   0.3] Opening the disks
...etc...

So this one instead dumps the noise into /dev/null