Remove references to <csignal> from AnalysisThread

The removed block_set member was unused.

src/zm_analysis_thread.cpp

@@ -5,7 +5,6 @@
 AnalysisThread::AnalysisThread(Monitor *p_monitor) {
   monitor = p_monitor;
   terminate = false;
-  //sigemptyset(&block_set);
 }
 
 AnalysisThread::~AnalysisThread() {

src/zm_analysis_thread.h

@@ -3,12 +3,10 @@
 
 #include "zm_monitor.h"
 #include "zm_thread.h"
-#include <csignal>
 
 class AnalysisThread : public Thread {
   private:
     bool terminate;
-    sigset_t block_set;
     Monitor *monitor;
 
   public: