MINOR: Fix an error message thrown when we run out of memory

Fixes a typo in an error message that can be seen by the end user when
the haproxy subsystem runs out of memory.

src/haproxy.c

@@ -765,7 +765,7 @@ static void mworker_reload()
 	return;
 
 alloc_error:
-	ha_warning("Failed to reexecute the master processs [%d]: Cannot allocate memory\n", pid);
+	ha_warning("Failed to reexecute the master process [%d]: Cannot allocate memory\n", pid);
 	return;
 }