BaseTools: Fixed bugs in CopyDict function

BaseTools: Fixed bugs in CopyDict function

https://bugzilla.tianocore.org/show_bug.cgi?id=1387

This patch is going to fix the regression issue which is
introduced by commit bf9e636605188e291d33ab694ff1c5926b6f0800.

This patch Remove the CopyDict incorrect usage for non-dict
input data. Add a check for CopyDict input.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>