[MCL-8260] Window title displays Minecraft Launcher unknown instead of Minecraft Launcher 1.6.84-j

Expected result : Window title displays Minecraft Launcher <version>, in this case Minecraft Launcher 1.6.84-j.

Actual result : Window title displays Minecraft Launcher unknown.

Steps to reproduce :
Run Minecraft launcher.

Severity : Only affect appearance, other launcher features work as expected.

Launcher log output :

[18:05:48 INFO]: Minecraft Launcher unknown (through bootstrap 100) started on windows...
[18:05:48 INFO]: Current time is Dec 2, 2017, 6:05:48 PM
[18:05:48 INFO]: System.getProperty('os.name') == 'Windows 10'
[18:05:48 INFO]: System.getProperty('os.version') == '10.0'
[18:05:48 INFO]: System.getProperty('os.arch') == 'amd64'
[18:05:48 INFO]: System.getProperty('java.version') == '9.0.1'
[18:05:48 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[18:05:48 INFO]: System.getProperty('sun.arch.data.model') == '64'
[18:05:48 INFO]: proxy == DIRECT
[18:05:48 INFO]: JFX is already initialized
[18:05:49 INFO]: Refreshing local version list...
[18:05:49 INFO]: Refreshing remote version list...
[18:05:50 INFO]: Refresh complete.
[18:05:50 INFO]: Loaded 0 profile(s); selected '(Default)'
[18:06:09 INFO]: Logging in with username & password