BaseTools: Add special handle for '\' use in Pcd Value

V2: Follow PEP8 to not multiples import on one line

Case:
gEfiOzmosisPkgTokenSpaceGuid.PcdBootLogFolderPath|L"\\Logs\\"|VOID*|12

Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=1287
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>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>

BaseTools/Source/Python/Common/Misc.py

@@ -24,6 +24,7 @@ import re
 import pickle
 import array
 import shutil
+from random import sample
 from struct import pack
 from UserDict import IterableUserDict
 from UserList import UserList
@@ -1236,7 +1237,8 @@ def IsFieldValueAnArray (Value):
     return False
 
 def AnalyzePcdExpression(Setting):
-    Setting = Setting.strip()
+    RanStr = ''.join(sample(string.ascii_letters + string.digits, 8))
+    Setting = Setting.replace('\\\\', RanStr).strip()
     # There might be escaped quote in a string: \", \\\" , \', \\\'
     Data = Setting
     # There might be '|' in string and in ( ... | ... ), replace it with '-'
@@ -1269,7 +1271,9 @@ def AnalyzePcdExpression(Setting):
             break
         FieldList.append(Setting[StartPos:Pos].strip())
         StartPos = Pos + 1
-
+    for i, ch in enumerate(FieldList):
+        if RanStr in ch:
+            FieldList[i] = ch.replace(RanStr,'\\\\')
     return FieldList
 
 def ParseDevPathValue (Value):