rebase: fix warning about ignoring tool option on rebase continue (issue4698)

Before this patch rebase --continue with specified --tool option outputs
warnings "tool option will be ignored". It is false statement because
in case of any merge conflicts it uses specified tool to resolve it.

This patch makes this warning appears only when user specified --tool
when running rebase --abort , in this case tool doesn't have any
sense

hgext/rebase.py

@@ -218,7 +218,7 b' def rebase(ui, repo, **opts):'
             if srcf or basef or destf:
                 raise util.Abort(
                     _('abort and continue do not allow specifying revisions'))
-            if opts.get('tool', False):
+            if abortf and opts.get('tool', False):
                 ui.warn(_('tool option will be ignored\n'))
 
             try:

tests/test-rebase-parameters.t

@@ -485,7 +485,6 b' Test --tool parameter:'
   $ hg resolve -m c2
   (no more unresolved files)
   $ hg rebase -c --tool internal:fail
-  tool option will be ignored
   rebasing 2:e4e3f3546619 "c2b" (tip)
   note: rebase of 2:e4e3f3546619 created no changes to commit
   saved backup bundle to $TESTTMP/b3/.hg/strip-backup/e4e3f3546619-b0841178-backup.hg (glob)