Fix shebangs and executable permissions

Files containing a shebang should be executable (examples/*.py)
Non-executable files should not contain a shebang (pymisp/...)

spotted with rpmlint

pymisp/api.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+
 # -*- coding: utf-8 -*-
 
 """Python API using the REST interface of MISP"""

pymisp/exceptions.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+
 # -*- coding: utf-8 -*-
 
 class PyMISPError(Exception):

pymisp/mispevent.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+
 # -*- coding: utf-8 -*-
 
 import datetime

pymisp/tools/neo4j.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 import glob

pymisp/tools/openioc.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+
 # -*- coding: utf-8 -*-
 
 import os

pymisp/tools/stix.py

@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
 try: