The output of 'nova-manage cell_v2 list_cells' command
has been modified since Idb306e4f854957fd2ded9ae061fc27f0ef768fc0 and
I96a6d5e59d33c65314fc187c0286ce3408d30bdc.
Fix the output of the command in the install documents.
Change-Id: I45d0e2ee1ff182347345af46f9a388f2884ba6cd
Closes-Bug: #1833647