Sparkleshare hangs on fetching files from private server

[Krzysztof Chrapka]

Sparkleshare hangs after issuing ssh-keyscan of custom host, and never proccedess futher.

Upstream bug: https://github.com/hbons/SparkleShare/issues/1905
Upstream solution: install newer version of sparkleshare

Output log:

$ sparkleshare start
20:16:04 | Environment | SparkleShare version: 1.5.0, Operating system: Unix (Unix 5.0.0.25)
xdg-open: unexpected option '-s'
Try 'xdg-open --help' for more information.
xdg-open: unexpected option '-s'
Try 'xdg-open --help' for more information.
This tool has been deprecated, use 'gio set' instead.
See 'gio help set' for more info.

20:16:04 | Auth | Imported key '/home/krzysztofchrapka/.config/sparkleshare/2019-08-13_19h11.key'
20:16:04 | Auth | The following keys may be used:
2048 SHA256:XygTEgN9+YC30XbM2Wt8NHsGEWXds5+B+8YGq6cHIyM /home/krzysztofchrapka/.ssh/id_rsa (RSA)
4096 SHA256:fc22ekGEFnciFpFvnJt/TRVlU/BH9yuePGZPU3JpndA /home/krzysztofchrapka/.config/sparkleshare/2019-08-13_19h11.key (RSA)
20:16:05 | Avatars | Invalid certificate for https://www.gravatar.com/
20:16:05 | Avatars | Error fetching avatar for my.private.email@somewhere: Error: TrustFailure (The authentication or decryption has failed.) at System.Net.WebClient.DownloadDataInternal (System.Uri address, System.Net.WebRequest& request) [0x0008a] in <bd46d4d4f7964dfa9beea098499ab597>:0
  at System.Net.WebClient.DownloadData (System.Uri address) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
  at System.Net.WebClient.DownloadData (System.String address) [0x00019] in <bd46d4d4f7964dfa9beea098499ab597>:0
  at (wrapper remoting-invoke-with-check) System.Net.WebClient:DownloadData (string)
  at SparkleShare.SparkleAvatars.GetAvatar (System.String email, System.Int32 size, System.String target_path) [0x0016f] in <5fddc956b41e4e8c85e8326eae4fa80c>:0

(mono:27223): Gtk-CRITICAL **: 20:16:05.640: gtk_window_set_default: assertion 'gtk_widget_get_can_default (default_widget)' failed
20:16:23 | Fetcher | /home/krzysztofchrapka/SparkleShare/.tmp/sync | Fetching folder: ssh://<email address hidden>/the/path/is/correct/believe/me
20:16:23 | Auth | Fetching host key for lalala.org
20:16:23 | Cmd | ssh-keyscan -t rsa -p 22 lalala.org
# lalala.org:22 SSH-2.0-OpenSSH_6.0p1 Debian-4+deb7u7

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: sparkleshare 1.5.0-2.1
ProcVersionSignature: Ubuntu 5.0.0-25.26~18.04.1-generic 5.0.18
Uname: Linux 5.0.0-25-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Aug 13 20:10:22 2019
InstallationDate: Installed on 2019-08-13 (0 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
PackageArchitecture: all
SourcePackage: sparkleshare
UpgradeStatus: No upgrade log present (probably fresh install)