Bug 916100 - [Contacts] Taapping on the disabled merge button when there are not contacts selected to be merged make it to change its colour.
Merge pull request #12295 from gtorodelvalle/contacts-bug-916100-footer-button-not-disabled

Bug 916100 - [Contacts] Taapping on the disabled merge button when there are not contacts selected to be merged make it to change its colour (r=jmcanterafonseca)