give worst-case 'merge' merge-tool lowest priority

Another tool had -10 already.  Since 'merge' is clearly a worst-case
tool (internal), lowering to -100 ensures there's plenty of room for
slightly better cases.

contrib/mergetools.hgrc

@@ -1,86 +1,86 b''
 # Some default global settings for common merge tools
 
 [merge-tools]
 kdiff3.args=--auto --L1 base --L2 local --L3 other $base $local $other -o $output
 kdiff3.regkey=Software\KDiff3
 kdiff3.regappend=\kdiff3.exe
 kdiff3.fixeol=True
 kdiff3.gui=True
 
 gvimdiff.args=--nofork -d -g -O $local $other $base
 gvimdiff.regkey=Software\Vim\GVim
 gvimdiff.regname=path
 gvimdiff.priority=-9
 
 merge.checkconflicts=True
-merge.priority=-10
+merge.priority=-100
 
 gpyfm.gui=True
 
 meld.gui=True
 meld.args=--label='local' $local --label='base' $base --label='other' $other
 
 tkdiff.args=$local $other -a $base -o $output
 tkdiff.gui=True
 tkdiff.priority=-8
 
 xxdiff.args=--show-merged-pane --exit-with-merge-status --title1 local --title2 base --title3 other --merged-filename $output --merge $local $base $other
 xxdiff.gui=True
 xxdiff.priority=-8
 
 diffmerge.regkey=Software\SourceGear\SourceGear DiffMerge\
 diffmerge.regname=Location
 diffmerge.priority=-7
 diffmerge.args=-nosplash -merge -title1=local -title2=merged -title3=other $local $base $other -result=$output
 diffmerge.checkchanged=True
 diffmerge.gui=True
 
 p4merge.args=$base $local $other $output
 p4merge.regkey=Software\Perforce\Environment
 p4merge.regname=P4INSTROOT
 p4merge.regappend=\p4merge.exe
 p4merge.gui=True
 p4merge.priority=-8
 
 tortoisemerge.args=/base:$base /mine:$local /theirs:$other /merged:$output
 tortoisemerge.regkey=Software\TortoiseSVN
 tortoisemerge.checkchanged=True
 tortoisemerge.gui=True
 tortoisemerge.priority=-8
 
 ecmerge.args=$base $local $other --mode=merge3 --title0=base --title1=local --title2=other --to=$output
 ecmerge.regkey=Software\Elli\xc3\xa9 Computing\Merge
 ecmerge.gui=True
 
 filemerge.executable=/Developer/Applications/Utilities/FileMerge.app/Contents/MacOS/FileMerge
 filemerge.args=-left $other -right $local -ancestor $base -merge $output
 filemerge.gui=True
 
 ; Windows version of Beyond Compare
 beyondcompare3.args=$local $other $base $output /ro /lefttitle=local /centertitle=base /righttitle=other /automerge /reviewconflicts /solo
 beyondcompare3.regkey=Software\Scooter Software\Beyond Compare 3
 beyondcompare3.regname=ExePath
 beyondcompare3.gui=True
 beyondcompare3.priority=-2
 
 ; Linux version of Beyond Compare
 bcompare.args=$local $other $base -mergeoutput=$output -ro -lefttitle=parent1 -centertitle=base -righttitle=parent2 -outputtitle=merged -automerge -reviewconflicts -solo
 bcompare.premerge=False
 bcompare.gui=True
 bcompare.priority=-1
 
 winmerge.args=/e /x /wl /ub /dl other /dr local $other $local $output
 winmerge.regkey=Software\Thingamahoochie\WinMerge
 winmerge.regname=Executable
 winmerge.checkchanged=True
 winmerge.gui=True
 winmerge.priority=-10
 
 araxis.regkey=SOFTWARE\Classes\TypeLib\{46799e0a-7bd1-4330-911c-9660bb964ea2}\7.0\HELPDIR
 araxis.regappend=\ConsoleCompare.exe
 araxis.priority=-2
 araxis.args=/3 /a2 /wait /merge /title1:"Other" /title2:"Base" /title3:"Local :"$local $other $base $local $output
 araxis.premerge=False
 araxis.checkconflict=True
 araxis.binary=True
 araxis.gui=True