trace: fix creation of systemtap files

The "exe_name" variable was renamed to exe['name'], so systemtap
files fail to build.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed