Changes in dreport to accept /tmp/ as a valid dir

In the dreport script there is a condition which checks for
'/tmp' only. When the user passes directory as '/tmp/' this
check fails. As a result the overall operation fails.
This commit fixes this by treating '/tmp/' as a valid directory.

Signed-off-by: Chirag Sharma <chirshar@in.ibm.com>
Change-Id: Ie11f96f0ff71bfb1fa4fedc59c40d8191116c5c6