apply-patch: prefix diff output with '> '

apply-patch: prefix diff output with '> '

When aiaiai responds to a mailing list that is monitored by patchwork, a
failure to apply a diff can cause patchwork to generate false positive
"patches" due to the diff in the email. This patch modifies aiaiai so
that it prefixes the output of the command with a '> ' which will
prevent patchwork from recognizing this as a diff with a patch inlined
to the reply.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>