QNX: Make patch_qnx_files() more generic

you can now pass the string to be replaced as a parameter.
by default it replaces the given regex with ''.

Change-Id: Iaa16b716d9f0792a2eed7e883a110d4c3442d777
Reviewed-by: Wolfgang Bremer <wbremer@blackberry.com>
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>