rev-branch-cache: have debugupdatecache warm rbc too

Since the "v2" format can be more performant than the "v1" format (thanks to
mmap), it is useful to be able to make sure it is present

mercurial/interfaces/repository.py

@@ -82,6 +82,7 CACHES_ALL = {
     CACHE_BRANCHMAP_SERVED,
     CACHE_BRANCHMAP_ALL,
     CACHE_BRANCHMAP_DETECT_PURE_TOPO,
+    CACHE_REV_BRANCH,
     CACHE_CHANGELOG_CACHE,
     CACHE_FILE_NODE_TAGS,
     CACHE_FULL_MANIFEST,

tests/test-branches.t

@@ -920,6 +920,18 Write operation write a full v2 files
   .hg/cache/rbc-revs-v1: size=160
   .hg/cache/rbc-revs-v2: size=168
 
+So does explicit cache upgrade
+  $ mv .hg/cache/rbc-names-v2 .hg/cache/rbc-names-v1
+  $ mv .hg/cache/rbc-revs-v2 .hg/cache/rbc-revs-v1
+  $ f --size .hg/cache/rbc-*
+  .hg/cache/rbc-names-v1: size=110
+  .hg/cache/rbc-revs-v1: size=168
+  $ hg debugupdatecache
+  $ f --size .hg/cache/rbc-*
+  .hg/cache/rbc-names-v1: size=110
+  .hg/cache/rbc-names-v2: size=110
+  .hg/cache/rbc-revs-v1: size=168
+  .hg/cache/rbc-revs-v2: size=168
 
 With invalid v1 data, we rewrite it too (as v2)