Merge branch 'bc/connect-plink' into maint

The connection initiation code for "ssh" transport tried to absorb differences between the stock "ssh" and Putty-supplied "plink" and its derivatives, but the logic to tell that we are using "plink" variants were too loose and falsely triggered when "plink" appeared anywhere in the path (e.g. "/home/me/bin/uplink/ssh"). * bc/connect-plink: connect: improve check for plink to reduce false positives t5601: fix quotation error leading to skipped tests connect: simplify SSH connection code path