[LTP] [PATCH 2/2] pec: Fix multiple event test

[Petr Vorel]

Hi Joerg,

Test is defined as #!/bin/bash which is not acceptable [1], I'm going to change
it as #!/bin/sh. Also note a need to check with checkbashism.

Kind regards,
Petr

[1] https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines#132-shell-coding-style