libtool.m4 correction

[Guido Draheim]

 # Add /usr/xpg4/bin/sed as it is typically found on Solaris
 # along with /bin/sed that truncates output.
 for lt_ac_sed in $lt_ac_sed_list /usr/xpg4/bin/sed; do
-  test ! -f $lt_ac_sed && break
+  test ! -f $lt_ac_sed && continue
   cat /dev/null > conftest.in
   lt_ac_count=0

On one of my build hosts the loop will break before
any good sed is being found even that there is one
good sed later in the path. The current cvs version
will break if any directory item in $PATH does not
contain an sed candidate.

> rpm -q libtool
libtool-1.5.8-3

savannah cvsweb shows the same line. Longstanding?