avocado.job: output a line break after Ctrl+C

Otherwise, the rest of the console UI ("PASS: ...") will stay in the same
line as the throbber.

Before the patch:
    ...
    TESTS     : 1
    (1/1) linuxbuild.py:  ^CPASS      : 0
    ERROR     : 0
    FAIL      : 0
    ...

After:
    ...
    TESTS     : 1
    (1/1) linuxbuild.py:  ^C
    PASS      : 0
    ERROR     : 0
    ...

Signed-off-by: Ademar de Souza Reis Jr <areis@redhat.com>