Add a test to make sure a new snapshot has the new value.
Change the length of the file so that the change is picked up.
Patch from @carlosmn to refresh the parent config before snapshotting.
ssl: dump the SSL ciphers in favour of TLS

All versions of SSL are considered deprecated now, so let's ask OpenSSl
to only use TLSv1. We still ask it to load those ciphers for
compatibility with servers which want to use an older hello but will use
TLS for encryption.

For good measure we also disable compression, which can be exploitable,
if the OpenSSL version supports it.
Merge pull request #2625 from libgit2/cmn/ssl-tls

ssl: dump the SSL ciphers in favour of TLS
Merge pull request #2622 from libgit2/refresh-config-snapshot

Refresh git configuration before looking for the tracking branch redux.