In the Launch Instance modal, if the user clicks on the button to import
a keypair, the networks listed in the Networking tab get duplicated.
The import keypair button calls `workflow_init` which in turn calls
`generate_networklist_html` which appended the networks to the list, not
clearing it beforehand.
This makes sure both Selected Networks and Available Networks lists are
emptied before the networks are added.
Fixes bug 1170193
Change-Id: Icb750caa08673068c509af6c8df1ad57a2a30d93
Signed-off-by: Tomas Sedovic <tomas@sedovic.cz>
0512a12d07