Use default parents for nonexistent branches.

If we don't per-game brentry data, make parent_branch return what would
be the parent, rather than NUM_BRANCHES.  Among other things, this
avoids leaking random branch choices in the ctrl-o screen (branches not
in the current game were never listed).

Also revert two piecemeal fixes that are now handled by the more general
code:
This reverts commit 259fcac8a0cba227ee4dc49cf5a7d5d2718cdc9c.
This reverts commit 81f5e101725dc1c0d5e96fc068a7b2b8d72b12ba.

1 files changed, 3 insertions, 2 deletions

diff --git a/crawl-ref/source/branch.cc b/crawl-ref/source/branch.cc
index 27af4510db..082141a960 100644
--- a/crawl-ref/source/branch.cc
+++ b/crawl-ref/source/branch.cc
@@ -38,7 +38,7 @@ bool is_hell_subbranch(branch_type branch)
 
 bool is_random_subbranch(branch_type branch)
 {
-    return (branches[branch].parent_branch == BRANCH_LAIR
+    return (parent_branch(branch) == BRANCH_LAIR
             && branch != BRANCH_SLIME)
            || branch == BRANCH_CRYPT
            || branch == BRANCH_FOREST;
@@ -87,5 +87,6 @@ branch_type parent_branch(branch_type branch)
 {
     if (brentry[branch].is_valid())
         return brentry[branch].branch;
-    return NUM_BRANCHES;
+    // If it's not in the game, use the default parent.
+    return branches[branch].parent_branch;
 }