BaseTools/Common: fix heap overrun in ReadMemoryFileLine ()

ReadMemoryFileLine () appends a NULL character to the string
it returns, but it failed to account for it in the allocation.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Yingke Liu <yingke.d.liu@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18047 6f19259b-4bc3-4df7-8a09-765794883524

BaseTools/Source/C/Common/MemoryFile.c

@@ -194,7 +194,7 @@ Returns:
     CharsToCopy = EndOfLine - InputFile->CurrentFilePointer;
   }
 
-  OutputString = malloc (CharsToCopy);
+  OutputString = malloc (CharsToCopy + 1);
   if (OutputString == NULL) {
     return NULL;
   }