Ensure self._l is not left in an only partially initialized state

If the timeout is reached and a reconnection was not successfull in that time, a ldap.SERVER_DOWN exception is raised.
If later on, when it's assured that the ldap server is running again, the connection is used again, the reconnection
is not performed and the ldap connection in an incosistent unbind state.

Traceback (most recent call last):
  File "reproduce.py", line 23, in <module>
    _ = lo.search_s('l=school,l=dev', ldap.SCOPE_SUBTREE, '(uid=Administrator)')
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 597, in search_s
    return self.search_ext_s(base,scope,filterstr,attrlist,attrsonly,None,None,timeout=self.timeout)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 997, in search_ext_s
    return self._apply_method_s(SimpleLDAPObject.search_ext_s,*args,**kwargs)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 935, in _apply_method_s
    return func(self,*args,**kwargs)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 591, in search_ext_s
    return self.result(msgid,all=1,timeout=timeout)[1]
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 503, in result
    resp_type, resp_data, resp_msgid = self.result2(msgid,all,timeout)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 507, in result2
    resp_type, resp_data, resp_msgid, resp_ctrls = self.result3(msgid,all,timeout)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 514, in result3
    resp_ctrl_classes=resp_ctrl_classes
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 521, in result4
    ldap_result = self._ldap_call(self._l.result4,msgid,all,timeout,add_ctrls,add_intermediates,add_extop)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 106, in _ldap_call
    result = func(*args,**kwargs)
ldap.INSUFFICIENT_ACCESS: {'desc': 'Insufficient access'}

Lib/ldap/ldapobject.py

@@ -1166,14 +1166,18 @@ def reconnect(self,uri,retry_max=1,retry_delay=60.0):
             counter_text,uri
           ))
         try:
-          # Do the connect
-          self._l = ldap.functions._ldap_function_call(ldap._ldap_module_lock,_ldap.initialize,uri)
-          self._restore_options()
-          # StartTLS extended operation in case this was called before
-          if self._start_tls:
-            SimpleLDAPObject.start_tls_s(self)
-          # Repeat last simple or SASL bind
-          self._apply_last_bind()
+          try:
+            # Do the connect
+            self._l = ldap.functions._ldap_function_call(ldap._ldap_module_lock,_ldap.initialize,uri)
+            self._restore_options()
+            # StartTLS extended operation in case this was called before
+            if self._start_tls:
+              SimpleLDAPObject.start_tls_s(self)
+            # Repeat last simple or SASL bind
+            self._apply_last_bind()
+          except ldap.LDAPError:
+            SimpleLDAPObject.unbind_s(self)
+            raise
         except (ldap.SERVER_DOWN,ldap.TIMEOUT):
           if __debug__ and self._trace_level>=1:
             self._trace_file.write('*** %s reconnect to %s failed\n' % (
@@ -1185,7 +1189,6 @@ def reconnect(self,uri,retry_max=1,retry_delay=60.0):
           if __debug__ and self._trace_level>=1:
             self._trace_file.write('=> delay %s...\n' % (retry_delay))
           time.sleep(retry_delay)
-          SimpleLDAPObject.unbind_s(self)
         else:
           if __debug__ and self._trace_level>=1:
             self._trace_file.write('*** %s reconnect to %s successful => repeat last operation\n' % (