plugin: rename signal call
plugin: rename signal call

There was a rename of the signal handler function for rt
signals.  This renames the plugin use to be consistent with the
non-plugin case.

BUG=None.
TEST=Local compile.

Change-Id: I5bf2e19754183022dbfe31fd1fdeceb83e07c18a
Signed-off-by: Matt Delco <cc00dab355d6ba859a968a53c875215dc9c89b79@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1846680
Reviewed-by: Zach Reizner <3374927928a53d04457674c546bd4de57c2044ec@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm