Use delete [] operator for arrays

This commit also fixes a memory leak occurring because of
non-deleted char arrays

Change-Id: Ic3e1dac213726e60a659a1362d64512a8867f788
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>