[test_camera] Do not dereference potentially bad fd

No check is done to see if open() succeeds.

Found with Coverity. Fixes: CID#1042618

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>
[eglplatform] Do not dereference potentially invalid fd

The returned fd from open() could be invalid. Do not dereference
without a check.

Found with Coverity. Fixes: CID#1061776

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>
[getprop] Correct sizeof check

Most likely it was not the intention to do sizeof a pointer to a char pointer.
It happens to be more or less the same but could cause portability issues.

Found with Coverity. Fixes: CID#1061777

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>