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.
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 1336221..b6145fc 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -1891,6 +1891,7 @@
 
 				if (nested_conds[nested_cond_lvl] == NESTED_COND_IF_TAKE ||
 				    nested_conds[nested_cond_lvl] == NESTED_COND_IF_SKIP ||
+				    nested_conds[nested_cond_lvl] == NESTED_COND_ELIF_TAKE ||
 				    nested_conds[nested_cond_lvl] == NESTED_COND_ELIF_SKIP) {
 					nested_conds[nested_cond_lvl] = NESTED_COND_ELIF_SKIP;
 				} else if (!*args[1] || *args[1] == '0') {