This does the "reverse" of HumanSize, i.e. maps a string to an int64
using SI prefixes for the extension.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: 13f07b636f014331a5d5dc0eac40d6ac9e5c9263
Component: engine