THRIFT-2602 fix missing dist files

- add automake 1.13 dependency to configure.ac and doc
- use serial-tests instead of .NOTPARALLEL (introduced by THRIFT-1829)

Patch: Roger Meier
diff --git a/test/py/Makefile.am b/test/py/Makefile.am
index 6b31769..2fe9b5a 100755
--- a/test/py/Makefile.am
+++ b/test/py/Makefile.am
@@ -16,7 +16,8 @@
 # specific language governing permissions and limitations
 # under the License.
 #
-.NOTPARALLEL:
+AUTOMAKE_OPTIONS = serial-tests
+
 THRIFT = $(top_srcdir)/compiler/cpp/thrift
 
 py_unit_tests = RunClientServer.py