Raw input reader command execution "fixes".

- Primarily working around an issue that occurs when threads
  concurrently create pipes and fork a child process.  See comment in
  code...

- Other minor cleanup of the code:  making sure the child process calls
  _exit() versus exit(), limits itself to few select system calls before
  the exec(), and closes more unused file descriptors.

src/main.cc

@@ -57,6 +57,7 @@ extern "C" void OPENSSL_add_all_algorithms_conf(void);
 #include "input/Manager.h"
 #include "logging/Manager.h"
 #include "logging/writers/Ascii.h"
+#include "input/readers/Raw.h"
 #include "analyzer/Manager.h"
 #include "analyzer/Tag.h"
 #include "plugin/Manager.h"
@@ -842,6 +843,8 @@ int main(int argc, char** argv)
 
 	init_event_handlers();
 
+	input::reader::Raw::ClassInit();
+
 	// The leak-checker tends to produce some false
 	// positives (memory which had already been
 	// allocated before we start the checking is