Fixes `Unselect From List` due to Selenium changes.
Fixes `Unselect From List` due to Selenium changes.

Since Selenium version 2.53.0 deselect_by_value/label returns boolean, and
Exception if element is not found.
This fix keeps compatibility with versions <=2.52.0.

rtomac/robotframework-selenium2library,HelioGuilherme66/robotframework-selenium2library,Gaurang033/Selenium2Library,Gaurang033/Selenium2Library,robotframework/SeleniumLibrary,HelioGuilherme66/robotframework-selenium2library,SergiuTudos/Selenium2Library,emanlove/robotframework-selenium2library,SergiuTudos/Selenium2Library,robotframework/SeleniumLibrary,Gaurang033/Selenium2Library,SergiuTudos/Selenium2Library,emanlove/robotframework-selenium2library,rtomac/robotframework-selenium2library,HelioGuilherme66/robotframework-selenium2library,emanlove/robotframework-selenium2library,rtomac/robotframework-selenium2library,robotframework/SeleniumLibrary