Reuse last suggestions if the same parameters are used

When a share is confirmed the suggestions are got to check if there is
an exact match. Usually the suggestions were already got with the same
parameters in order to fill the autocomplete dropdown, so to avoid a
superfluous request now the last suggestions are reused when got again,
although only if the same parameters as the last time are used.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>