trace-cmd: Fix NULL pointer being passed to memcpy

Link: http://lkml.kernel.org/r/20171016165542.13038-3-mikesart@fastmail.com

Signed-off-by: Michael Sartain <mikesart@fastmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
1 file changed