Fix bug STATISTICS

STATISTICS Always resets to zero

efav_update_post_meta(... 
	if ($efav_val == -1 && $efav_oldval == 0 && $efav_oldval !== 1) {
    		$efav_val = 0;
	} else { 
  	   //   $efav_oldval = 0;  this variable always resets to zero  
		$efav_val = $efav_oldval + $efav_val;
	}