rpm/configure.sh: Remove unnecessary directories

These were introduced in change 18c6b647 to support
storing Mock's cache and chroot in the workspace.
Most of this was reverted in commit abc1705b.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
rpm/configure.sh: Tidy up script

Signed-off-by: Euan Harris <euan.harris@citrix.com>
Merge pull request #511 from euanh/build-improvements

Build improvements