Use bitwise '&' instead of logical '&&'

Use bitwise '&' instead of logical '&&'

Make two instances of the same change. Change bitwise AND (&) to logical
AND (&&).

Currently the code uses a bitwise AND between two boolean values.

In the first instance;

The first operand is a flag that has been bitwise combined with a bit
mask to get a boolean value as to whether a file has group write
permissions set.

The second operand used is a struct member that is intended as a
boolean flag not a bit mask.

In the second instance the argument is the same except with world write
permissions instead of group write (S_IWOTH, S_IWGRP).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Closes #6684
Closes #6722