config: rename `revlog` section into `storage`

The idea was suggested by Gregory Szorc on IRC. It is more generic and seems
better. It is probably best to rename the section before it ever makes into an
official (non-rc) release.

The only config option currently in this section have been prefixed with
`revlog` to clarify it applies to `revlog` related storage.

mercurial/configitems.py

@@ -927,7 +927,7 b" coreconfigitem('progress', 'width',"
 coreconfigitem('push', 'pushvars.server',
     default=False,
 )
-coreconfigitem('revlog', 'optimize-delta-parent-choice',
+coreconfigitem('storage', 'revlog.optimize-delta-parent-choice',
     default=True,
     alias=[('format', 'aggressivemergedeltas')],
 )

mercurial/help/config.txt

@@ -1773,13 +1773,13 b' have a definite end point.'
 
 Alias definitions for revsets. See :hg:`help revsets` for details.
 
-``revlog``
+``storage``
 ----------
 
 Control the strategy Mercurial uses internally to store history. Options in this
 category impact performance and repository size.
 
-``optimize-delta-parent-choice``
+``revlog.optimize-delta-parent-choice``
     When storing a merge revision, both parents will be equally considered as
     a possible delta base. This results in better delta selection and improved
     revlog compression. This option is enabled by default.

mercurial/localrepo.py

@@ -668,8 +668,8 b' class localrepository(object):'
         manifestcachesize = self.ui.configint('format', 'manifestcachesize')
         if manifestcachesize is not None:
             self.svfs.options['manifestcachesize'] = manifestcachesize
-        deltabothparents = self.ui.configbool('revlog',
-                                              'optimize-delta-parent-choice')
+        deltabothparents = self.ui.configbool('storage',
+            'revlog.optimize-delta-parent-choice')
         self.svfs.options['deltabothparents'] = deltabothparents
         self.svfs.options['lazydeltabase'] = not scmutil.gddeltaconfig(self.ui)
         chainspan = self.ui.configbytes('experimental', 'maxdeltachainspan')

tests/test-generaldelta.t

@@ -146,7 +146,7 b' Test revlog.optimize-delta-parent-choice'
 - Verify aggressive merge uses p2 (commit 0) as delta parent
   $ hg up -q -C 1
   $ hg merge -q 0
-  $ hg commit -q -m merge --config revlog.optimize-delta-parent-choice=yes
+  $ hg commit -q -m merge --config storage.revlog.optimize-delta-parent-choice=yes
   $ hg debugdeltachain -m
       rev  chain# chainlen     prev   delta       size    rawsize  chainsize     ratio   lindist extradist extraratio
         0       1        1       -1    base         59        215         59   0.27442        59         0    0.00000