BaseTools: create and use a standard shared variable for '*'

add a variable for the string '*' and then use it instead of lots of '*'

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by : Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/GenFds/GenFds.py

@@ -653,7 +653,7 @@ class GenFds(object):
                             FileGuidList.append(FileStatementGuid)
                         Name = []
                         FfsPath = os.path.join(GenFdsGlobalVariable.FvDir, 'Ffs')
-                        FfsPath = glob(os.path.join(FfsPath, FileStatementGuid) + '*')
+                        FfsPath = glob(os.path.join(FfsPath, FileStatementGuid) + TAB_STAR)
                         if not FfsPath:
                             continue
                         if not os.path.exists(FfsPath[0]):