manifest: Remove excessive catch of BaseExceptions

Exceptions inheriting directly from BaseException are not
automatically caught by "except Exception", so there
is no need to explicitly manage them.

Change-Id: Ic10764af4a6c05d1162f8b21651e7864ed742286

manifest_xml.py

@@ -1328,12 +1328,7 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                     )
                 # should isolate this to the exact exception, but that's
                 # tricky.  actual parsing implementation may vary.
-                except (
-                    KeyboardInterrupt,
-                    RuntimeError,
-                    SystemExit,
-                    ManifestParseError,
-                ):
+                except (RuntimeError, ManifestParseError):
                     raise
                 except Exception as e:
                     raise ManifestParseError(