Update default hash algorithm (md5 -> sha1) used for generating
the server and CA certificates.

Default support for md5 has been removed for TLS 1.2 and OTP-15248
introduced a check for the whole {hash, signature} algorithm pair
as defined by RFC5246.

Change-Id: I964914914f522c10ef11c8c7c72bb9e4a0c38010

A couple of test machines seem to have slow networking (?), so the remote eldap server initialization is aborted in init_per_suite

If underlying tcp connection is closed and LDAP operation returned tcp error,
then client applications tend to close ldap handle with eldap:close.
This will cause do_unbind to throw gen_tcp_error, which is unhandled
and will be sent to linked process as {nocatch, {gen_tcp_error, ...}}.
eldap should ignore gen_tcp_error during close, because it will be closing anyway.