worktree: rename copy-pasted variable

As the commit message of 04a3dfb8b5 ("worktree.c: check whether branch
is bisected in another worktree", 2016-04-22) indicates, the function
`is_worktree_being_bisected()` is based on the older function
`is_worktree_being_rebased()`. This heritage can also be seen in the
name of the variable where we store our return value: It was never
adapted while copy-editing and remains as `found_rebase`.

Rename the variable to make clear that we're looking for a bisect(ion),
nothing else.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

worktree.c

@@ -365,15 +365,15 @@ int is_worktree_being_bisected(const struct worktree *wt,
 			       const char *target)
 {
 	struct wt_status_state state;
-	int found_rebase;
+	int found_bisect;
 
 	memset(&state, 0, sizeof(state));
-	found_rebase = wt_status_check_bisect(wt, &state) &&
+	found_bisect = wt_status_check_bisect(wt, &state) &&
 		       state.branch &&
 		       starts_with(target, "refs/heads/") &&
 		       !strcmp(state.branch, target + strlen("refs/heads/"));
 	wt_status_state_free_buffers(&state);
-	return found_rebase;
+	return found_bisect;
 }
 
 /*