Fix numbering of steps in proxy section of install_multinode

Steps were numbered 1, 2, (note reset), 1, 2, etc. Then a user says:
"I'm on Step 2 in Proxy section, er..."

See a bug, fix a bug.

Change-Id: If6f32b3a33e1070e705812df7ab299e6736c9806
Merge "Fix numbering of steps in proxy section of install_multinode"