Log reason connection on port 22 of a failed VM

[yachub]

Currently, when vmpooler waits for a VM to become responsive, it tries to connect to a socket on port 22. If it fails, no error information is saved or logged anywhere.
Change this to log this error somewhere.

[isaac-jha]

[2023-08-18 13:04:07] [!] [fedora-36-x86_64] 'snowy-unison' marked as 'failed' after 15 minutes with ssh error: Connection timed out - Broken pipe