Memory leaks

[janus]

Memory leaks while running example tcpecho

`
==4678==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 5 byte(s) in 1 object(s) allocated from:
#0 0x7ff04461e30f in strdup (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x6230f)
#1 0x44f3d5 in cpy_arg test/picoapp.c:156
#2 0x4532c2 in app_tcpecho /home/emeka/buildtool/sample/picotcp/test/examples/tcpecho.c:129
#3 0x450bd6 in main test/picoapp.c:630
#4 0x7ff043def82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

`