BUG/MINOR: config: add a missing "ELIF_TAKE" test for ".elif" condition evaluator

This missing state was causing a second elif condition to be evaluated
after a first one succeeded after a .if failed. For example in the test
below the else would be executed:

     .if    0
     .elif  1
     .elif  0
     .else
     .endif

No backport is needed, this is 2.4-only.
1 file changed