bootchartd.in: no bashism

No bashism in bootchartd.in, so use /bin/sh.

Upstream-Status: Pending

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Max Eliaser <max.eliaser@intel.com>
Merge pull request #58 from Max-E/master

Use /bin/sh instead of /bin/bash in bootchartd script