update www/guacamole-client to 0.9.10

Changelog: https://github.com/glyptodon/guacamole-client/commits/0.9.10-incubating

• Updated to 0.9.10
• Updated license to APACHE20

PR: 216351
Submitted by: ultima1252@gmail.com (maintainer)
Reviewed by: matthew
Approved by: matthew (mentor)
Differential Revision: https://reviews.freebsd.org/D9283