[PATCH] Fix problems reported by static code analyser

[Anderson Sasaki <ansasaki@xxxxxxxxxx>]

Hello,

Follows attached a set of patches for problems reported by a static code analyser.

The first patch is a fix to possible memory leak in examples/samplesftp.c. The second is a style re-formatting.
The rest of the patches are changes to add null checks in tests and one fix to a possible memory in tests/unittests/torture_pki_dsa.c.

The changes can also be reviewed in:

https://gitlab.com/ansasaki/libssh-mirror/merge_requests/12

Best Regards,
Anderson