perf inject: Don't use globals where not needed to

Some variables were global but used in just one function, so move it to
where it belongs.

Leftover from patch at the beggining of this series.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-9cer20zhw64wbxyb0zias82i@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>