[analyzer] SATestBuild.py: Fix handling invalid plists after 2to3 conversion.

The updated plistlib throws a different exception class.
diff --git a/clang/utils/analyzer/SATestBuild.py b/clang/utils/analyzer/SATestBuild.py
index 7ca0544..02eb887 100755
--- a/clang/utils/analyzer/SATestBuild.py
+++ b/clang/utils/analyzer/SATestBuild.py
@@ -58,7 +58,7 @@
 import sys
 import threading
 import time
-from xml.parsers.expat import ExpatError
+
 try:
     import queue
 except ImportError:
@@ -493,7 +493,7 @@
             if not Data['files']:
                 os.remove(P)
                 continue
-        except ExpatError as e:
+        except plistlib.InvalidFileException as e:
             print('Error parsing plist file %s: %s' % (P, str(e)))
             continue