1.2.1 pre-release testing

[jcguu95]

Hi all!

First time posting here. Please let me know if I missed anything.

This is about my testing of 1.2.1 pre-release
(<https://ci.guix.gnu.org/build/175632/details>). I wiped out my machine
and installed it two times. Here are some summary about the experience.

1. Graphical Installation

   I chose the graphical method for the first installation. Everything
   went well, except my wired internet connection failed as it
   indicated. Weirdly enough, my ethernet cable has been always on my
   machine for a while, and never failed. Anyway, I managed to get wifi
   working, and that helped complete my installation process.

2. CLI-based Installation

   2.1. Better support for using git during installation process?

   Before `guix system init /mnt/etc/config.scm /mnt', I'd like to getch
   config.scm from my github repo. So I ran `guix package -i git'. But
   when I `git clone ...' as usual, there's an error "git:
   'remote-https' is not a git command .See 'git --help'".

   What's going on? Why does `git clone' fails when I'm installing guix
   system?

   2.2. Unexpected failure

   After running `guix system init /mnt/etc/config.scm /mnt' for 5 to 10
   minutes, I got the error

   ,----
   |    substitute: updating substitutes from 'https://ci.guix.gnu.org'... 
0.0%guix substitute: error: TSL error in procedure 'write_to_session_port': 
Resource temporarily unavailable, try again.
   | 
   |    guix system: error: 
`/gnu/store/1nmwil4cs...vc2p-guix-1.2.0-21.4dff6ec/bin/guix substitute` died 
unexpectedly
   |    root@gnu ~# _
   `----

   Retrying it did resolve the problem. And I got a working guix system
   out of it :)



In summary, though there was some minor issue, I was able/lucky to
resolve it. Thanks for all the hard work. And please feel free to let me
know if I can help further.

Cheers,

Jin