A directory is empty when it doesn't contain files or folders.
We can exploit QDirIterator::hasNext() to check whether this is the
case. This is efficient since it doesn't list the whole folder (in the
non-empty case).
Test cases are added for both the empty and non-empty cases.
Change-Id: I0f7e26782c0f97f9c16f928dab6cae37927875d8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
3f455a4b53