libext2: Fix EXT2_LIB_SOFTSUPP masking

libext2: Fix EXT2_LIB_SOFTSUPP masking

EXT2_LIB_SOFTSUPP_INCOMPAT_* are supposed to be bitmasks
of features which can be opened even though they are
under development.  The intent is that these are masked
out of the features list, so that they will be ignored
on open.

However, the code does a logical not vs. a bitwise not:

	features &= !EXT2_LIB_SOFTSUPP_INCOMPAT;

which will not have the desired effect...

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>