MINOR: mworker: support a configurable maximum number of reloads

This patch implements a new global parameter for the master-worker mode.
When setting the mworker-max-reloads value, a worker receive a SIGTERM
if its number of reloads is greater than this value.
diff --git a/include/proto/mworker.h b/include/proto/mworker.h
index bf8317f..86f0904 100644
--- a/include/proto/mworker.h
+++ b/include/proto/mworker.h
@@ -35,5 +35,6 @@
 
 int mworker_ext_launch_all();
 
+void mworker_kill_max_reloads(int sig);
 
 #endif /* PROTO_MWORKER_H_ */