Free attributes before return NULL

[ltx2018]

fix memleak in GetTokenFromStream()

[ltx2018]

And here is the reproduce testcode(based from oss-fuzz):
poc.zip

[geoffmcl]

@ltx2018 thank you for this next PR... and the poc.c sample code, to reproduce...

But actually you can use tidy itself, like just running -

$ echo "<?xml a" | valgrind tidy -q

And applying your 9e05e16 patch clears the heap summery - in use at exit: 0 bytes in 0 blocks - great...

Look forward to others testing this, and reporting... thanks...

Baring any negative reports, but do not expect any, will get to merging this soonest... thanks...

[ltx2018]

@ltx2018 thank you for this next PR... and the poc.c sample code, to reproduce...

But actually you can use tidy itself, like just running -

$ echo "<?xml a" | valgrind tidy -q

And applying your 9e05e16 patch clears the heap summery - in use at exit: 0 bytes in 0 blocks - great...

Look forward to others testing this, and reporting... thanks...

Baring any negative reports, but do not expect any, will get to merging this soonest... thanks...

Thanks for the review and comments

[geoffmcl]

@ltx2018 PR now merged... thanks...