BaseTools: Roll back code modify by commit 9e47e6f908

Roll back code modify by commit 9e47e6f908,
if ForceRebase not False or True, the GenFv command not need add parameter

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yunhua Feng <yunhuax.feng@intel.com>

BaseTools/Source/Python/GenFds/GenFdsGlobalVariable.py

@@ -574,9 +574,9 @@ class GenFdsGlobalVariable:
         if BaseAddress:
             Cmd += ("-r", BaseAddress)
 
-        if not ForceRebase:
+        if ForceRebase == False:
             Cmd += ("-F", "FALSE")
-        else:
+        elif ForceRebase == True:
             Cmd += ("-F", "TRUE")
 
         if Capsule: