fedora 22 dnf upgrade failed to sync

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Symptom

sudo dnf update : excerpt

[steve@ip98-167-78-229 lucky_you.2007]$ sudo dnf upgrade
Failed to synchronize cache for repo 'fedy' from 
'http://download.opensuse.org/repositories/home:/satya164:/fedy/Fedora_22/': 
Cannot download repomd.xml: Cannot download repodata/repomd.xml: 
All mirrors were tried, disabling.
Last metadata expiration check performed 0:47:49 ago on Thu Apr 14 07:33:10 2016.
Dependencies resolved.
========================================================================
 Package                  Arch      Version       Repository    Size
========================================================================
Upgrading:
 dracut                   x86_64    041-15.fc22   updates       324 k
 dracut-config-rescue     x86_64    041-15.fc22   updates        45 k
...

Transaction Summary
========================================================================
Upgrade  21 Packages

Total download size: 7.9 M
Is this ok [y/N]: 

Rig

fedora 22 64 bit, cinnamon 2.6.13, 16gb memory

Background

Boot disk recently died; decided to recover by re-installing everything, starting with Fedora 22 Live. kde proved problematic so switched to cinnamon. Then had trouble installing fedy. With the (partial or full) failures shown below, I (mistakenly) did not retain the error messages.

The following seemed to totally fail:

su -c "curl https://satya164.github.io/fedy/fedy-installer -o fedy-installer && chmod +x fedy-installer && ./fedy-installer"

The following seemed to either partially or totally fail. I noticed what seemed to be error messages.

went to http://sourceforge.net/projects/fedorautils/
selected the (green) download button
downloaded fedy-installer
in a terminal : 
  su 
  made file executable (chmod 777)
  then executed it : ./fedy-installer

Because of the error messages in the previous approach, I then:

google searched : fedora 22 install fedy
found and played a youtube video : https://www.youtube.com/watch?v=a4d0L_CL9jA
the video pointed to http://folkswithhats.org/
on that webpage the following command was given:  
bash -c 'su -c "curl http://folkswithhats.org/fedy-installer -o fedy-installer && chmod +x fedy-installer && ./fedy-installer"'

The above seemed to succeed, "Fedy" was added to the cinnamon start Menu. In fact, (partially unrelated) after a previous (terminal) attempt to install Adobe Flash failed, the Fedy installer successfully installed it. This was verified via a webpage that requires Flash.

Long Term

Actually, I've been "living off of" a usb-connected external hard disk, using it as a boot disk. New hard disks coming in a few days; then I'll (again) re-install from scratch, starting with Fedora 22 Live.

Questions

1. Why is sudo dnf upgrade yielding an error message? (In linux-newbie terms) what does the message mean? Was the message (plausibly) caused by my 2nd Fedy installer attempt, executing ./fedy-installer?

2. With fedy apparently successfully installed and dnf upgrade apparently working correctly, is the error message "harmless"?

3. Assuming no re-install, is there a way of removing the error message (prefer a terminal command, rather than low-level editing of some file on the root partition).

4. Assuming that I re-install from scratch and bypass the two failed attempts to install fedy, should I expect the error message to not appear?