Fix Unix multisession/websession licensing to recognize IPv6 addresses and not to confuse them with odd ut_host entries from 'screen'.
Previous Release Behavior
Multisession & Websession licenses require client IP address. On Linux, the utmp ut_host field is used to locate the client IP address. However, processes managed by the Linux "screen" command save the owning pty name here with a leading ":". Now that IPv6 is common, some IPv6 addresses begin with a ":", causing them to be identified as "screen" sessions, but the owning pty is not found and they end up defaulting to "localhost".
Current Release Behavior
Properly parse the address found in ut_host, and determine if it is a valid IPv4 or IPv6 address. Only if it is not a valid address is the test for a "screen" session applied.