BaseTools:change some incorrect parameter defaults

BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=1858

for Dict={},There are pitfalls in the way this default parameter is set
and Dict is not used in functions, other functions have these two cases,
I will change some incorrect parameter defaults

This patch is going to fix this issue

Cc: Liming Gao <liming.gao@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/GenFds/EfiSection.py

@@ -49,7 +49,7 @@ class EfiSection (EfiSectionClassObject):
     #   @param  Dict        dictionary contains macro and its value
     #   @retval tuple       (Generated file name list, section alignment)
     #
-    def GenSection(self, OutputPath, ModuleName, SecNum, KeyStringList, FfsInf = None, Dict = {}, IsMakefile = False) :
+    def GenSection(self, OutputPath, ModuleName, SecNum, KeyStringList, FfsInf = None, Dict = None, IsMakefile = False) :
 
         if self.FileName is not None and self.FileName.startswith('PCD('):
             self.FileName = GenFdsGlobalVariable.GetPcdValue(self.FileName)
@@ -76,6 +76,8 @@ class EfiSection (EfiSectionClassObject):
 
         """If the file name was pointed out, add it in FileList"""
         FileList = []
+        if Dict is None:
+            Dict = {}
         if Filename is not None:
             Filename = GenFdsGlobalVariable.MacroExtend(Filename, Dict)
             # check if the path is absolute or relative