clean PLC log only if there is something to clean

Otherwise exception happens in Beremiz service.

Traceback (most recent call last):
File "/home/developer/WorkData/PLC/beremiz/beremiz/connectors/PYRO/_init_.py", line 113, in catcher_func
return func(*args, **kwargs)
File "/home/developer/WorkData/PLC/beremiz/beremiz/connectors/PYRO/_init_.py", line 194, in my_local_func
return RemotePLCObjectProxy._getattr_(attrName)(*args, **kwargs)
File "/usr/lib/python2.7/dist-packages/Pyro/core.py", line 381, in _call_
return self._send(self._name, args, kwargs)
File "/usr/lib/python2.7/dist-packages/Pyro/core.py", line 456, in _invokePYRO
return self.adapter.remoteInvocation(name, Pyro.constants.RIF_VarargsAndKeywords, vargs, kargs)
File "/usr/lib/python2.7/dist-packages/Pyro/protocol.py", line 457, in remoteInvocation
return self._remoteInvocation(method, flags, *args)
File "/usr/lib/python2.7/dist-packages/Pyro/protocol.py", line 532, in _remoteInvocation
answer.raiseEx()
File "/usr/lib/python2.7/dist-packages/Pyro/errors.py", line 72, in raiseEx
raise self.excObj
AttributeError: 'PLCObject' object has no attribute '_ResetLogCount'
+--- This exception occured remotely (Pyro) - Remote traceback:
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/Pyro/protocol.py", line 719, in _handleInvocation2
res = obj.Pyro_dyncall(req[1],flags,req[3]) # (method,flags,args)
File "/usr/lib/python2.7/dist-packages/Pyro/core.py", line 108, in Pyro_dyncall
return getattr(self.delegate or self,method) (args,*keywords)
File "/home/developer/WorkData/PLC/beremiz/beremiz/runtime/PLCObject.py", line 101, in ResetLogCount
if self._ResetLogCount is not None:
AttributeError: 'PLCObject' object has no attribute '_ResetLogCount'
+--- End of remote traceback

<?xml version='1.0' encoding='utf-8'?>
<PyFile xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <variables>
    <variable name="Test_Python_Var" type="INT" initial="4"/>
    <variable name="Second_Python_Var" type="INT" initial="5"/>
  </variables>
  <globals>
    <xhtml:p><![CDATA[
import time,sys,ctypes
Python_to_C_Call = PLCBinary.Python_to_C_Call
Python_to_C_Call.restype = ctypes.c_int
Python_to_C_Call.argtypes = [ctypes.c_int, ctypes.POINTER(ctypes.c_int)]

def MyPythonFunc(arg):
    i = ctypes.c_int()
    if(Python_to_C_Call(arg, i)):
        res = i.value
        print "toC:", arg, "from C:", res, "FBID:", FBID
    else:
        print "Failed Python_to_C_Call failed"
        res = None
    print "Python read PLC global :",PLCGlobals.Test_Python_Var
    PLCGlobals.Second_Python_Var = 789
    sys.stdout.flush()
    return res

async_error_test_code = """
def badaboom():
    tuple()[0]

import wx
def badaboomwx():
    wx.CallAfter(badaboom)

from threading import Timer
a = Timer(3, badaboom)
a.start()

b = Timer(6, badaboomwx)
b.start()
"""
]]></xhtml:p>
  </globals>
  <init>
    <xhtml:p><![CDATA[
global x, y
x = 2
y = 5
print "py_runtime init:", x, ",", y
]]></xhtml:p>
  </init>
  <cleanup>
    <xhtml:p><![CDATA[
print "py_runtime cleanup"
]]></xhtml:p>
  </cleanup>
  <start>
    <xhtml:p><![CDATA[
global x, y
print "py_runtime start", x * x + y * y
]]></xhtml:p>
  </start>
  <stop>
    <xhtml:p><![CDATA[
print "py_runtime stop"
]]></xhtml:p>
  </stop>
</PyFile>