Fix buffer overflow in syren utility

Patch for https://code.google.com/p/android/issues/detail?id=68268



A length check for the argv[2] was added in order to prevent buffer
overflow.  Also replace strcpy with strlcpy.

Signed-off-by: nks <nks@sixserv.org>
Change-Id: If65b83e9b658315c672e684f64e3ae00e69fac31