ktest: Enable user input to the console

Allow the user to send input to the console by putting the terminal in
cbreak mode (to allow reading stdin one character at a time) and copying
all stdin data to the console's pty.

Link: http://lkml.kernel.org/r/bb1bbe7d202c95a3ce7894cfffdd8c725875978e.1422473610.git.jpoimboe@redhat.com



Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>