qa/cephfs: set omit_sudo for cmd mounting FUSE conn dir

qa/cephfs: set omit_sudo for cmd mounting FUSE conn dir

vstart_runner.py removes sudo from the command arguments when "omit_sudo"
is not explicitly set to "False". This leads to 2 error messages in output
of vstart_runner.py which are copied at the end of this commit message.
Setting "omit_sudo=False" for the execution of command should remove both
of these error messages.

This also fixes the potential crash of vstart_runner.py when the FUSE
connections directory is not mounted on the machine and it requires
superuser privileges to mount it.

The 2 error messages copied as it is from the log -

DEBUG:__main__:"sudo" was omitted from the following cmd args before execution and logging using function overriding; check vstart_runner.py for more details.
DEBUG:__main__:> sudo mount -t fusectl /sys/fs/fuse/connections /sys/fs/fuse/connections
mount: /sys/fs/fuse/connections: must be superuser to use mount.

Signed-off-by: Rishabh Dave <ridave@redhat.com>