Return statements are only valid inside functions" 

(Backport to 4.7.2)

Wrapping evaluate logic into a function to deal with corner case where
'return' is not at the beginnign of the script. Tested with all Browser
jUnit tests.

Change-Id: Ieeffd891db64cf4c719ee097ea9939fd8352c2d9
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>