Fix the message shown when running 'collect logs -H'

[mattsfuller]

When running the command 'collect logs -H ', the first line shown reads as 'Downloading logs from all the nodes'. This is incorrect. Change this line to show only the names of nodes from which logs are being downloaded.
See below for an example run:
S ./prestoadmin/presto-admin collect logs -H 172.30.1.55,172.30.1.57
Downloading logs from all the nodes...
Warning: Local file /tmp/presto-debug/logs/172.30.1.55/launcher.log already exists and is being overwritten.
Warning: Local file /tmp/presto-debug/logs/172.30.1.57/launcher.log already exists and is being overwritten.
logs archive created: /tmp/presto-debug-logs.tar.bz2
[root@ip-172-30-1-57 ~]#