Sync patch r16338 from main trunk.

BaseTools: Fix a cleanall issue.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yingke Liu <yingke.d.liu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

(cherry picked from commit 3cd9371f68ea90aab26b0cde94f1916f56036df2)

git-svn-id: svn://svn.code.sf.net/p/edk2/code/branches/UDK2014.SP1/BaseTools@16438 6f19259b-4bc3-4df7-8a09-765794883524