Use floats instead of integer in memory calculation of admin dashboard

In the case that hypervisors have large amounts of memory, you'll find that
the dashboard reports improper memory usage when in the TB and PB range.
For example, 1.95 TB as an integer equals 1 so we convert to float instead.

Fixes bug: 1313009

Change-Id: Ie107986fa3ed9aad5c68c34353cdfc5943788069
Merge "Use floats instead of integer in memory calculation of admin dashboard"