BaseTools/UPT:merge UPT Tool use Python2 and Python3

In UPT Tool,merge python2 and python3

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/UPT/UPT.py

@@ -21,6 +21,7 @@ UPT
 #
 import locale
 import sys
+from imp import reload
 encoding = locale.getdefaultlocale()[1]
 if encoding:
     reload(sys)