* fix compile warnings: reopen() usage

DaemonLinux.cpp

@@ -73,10 +73,10 @@ namespace i2p
 					return false;
 				}
 
-				// close stdin/stdout/stderr descriptors
-				freopen("/dev/null", "r", stdin);
-				freopen("/dev/null", "w", stdout);
-				freopen("/dev/null", "w", stderr);
+				// point std{in,out,err} descriptors to /dev/null
+				stdin  = freopen("/dev/null", "r", stdin);
+				stdout = freopen("/dev/null", "w", stdout);
+				stderr = freopen("/dev/null", "w", stderr);
 			}
 
 			// Pidfile