Don't try to start qmlls if the found path doesn't exist.
When there is no Qt version found in the project (this happens
when you open a qml file without providing its build folder, or
open it without the project info so no linked Qt version is found)
we might end up with incorrect path where no actual qml executable
exist for that path. Check the existence of the binary before assigning
it as the path for qmlls.
Fixes: QTCREATORBUG-31207
Change-Id: I626ace796401e72462eb850d4bd88c1ef51cf53a
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>
60b0d88df9