Don't mention maintainer-clean, since `make bootstrap' does this now.

(With the exception that it does not remove Makefile from lisp/ or src/).

INSTALL.CVS

@@ -44,13 +44,8 @@ To update loaddefs.el (and similar files), do:
   $ make autoloads
 
 If either of the above partial procedures fails, try "make bootstrap".
-
-Very occasionally changes in the source can introduce
-incompatibilities with previous builds.  If a bootstrap fails, as a
-last resort try "make maintainer-clean" before configuring and
-bootstrapping again.  If CPU time is not an issue, the most thorough
-way to rebuild, and avoid any spurious problems, is always to use this
-method.
+If CPU time is not an issue, the most thorough way to rebuild, and
+avoid any spurious problems, is always to use this method.
 
 Users of non-Posix systems (MS-Windows etc.) should run the
 platform-specific configuration scripts (nt/configure.bat, config.bat,