plugins/elements/gstfilesrc.c: Do not use mmap() by default since there are a number...

plugins/elements/gstfilesrc.c: Do not use mmap() by default since there are a number of error conditions that we woul...

Original commit message from CVS:
* plugins/elements/gstfilesrc.c: (gst_file_src_class_init):
Do not use mmap() by default since there are a number of error
conditions that we would like to handle in a non-fatal way that
will result in a SIGBUS if we use mmap(). Examples: external
devices (USB harddrive, portable music player) being unplugged
while in use; file on mounted CD/DVD that can't be read because
the medium is partly damaged. Fixes #348455 and #348475.