tests: avoid empty AT_DATA contents, for zsh.

[Ralf Wildenhues]

This fixes the remaining testsuite failures with zsh 4.3.10 on FreeBSD.

cat >file <<EOF
EOF

produces an empty file with sh, but a file containing a newline with
zsh, even after 'emulate sh'.  autoconf.texi patch coming up too, I
guess.

Cheers,
Ralf

    tests: avoid empty AT_DATA contents, for zsh.
    
    * tests/libtoolize.at (libtoolize macro serial update)
    (libtoolize config files serial update, LIBTOOLIZE_OPTIONS):
    Do not create empty files with AT_DATA, the latter is documented
    to require a final newline.  Fixes testsuite failures with zsh
    4.3.10.

diff --git a/tests/libtoolize.at b/tests/libtoolize.at
index fa229b9..541753b 100644
--- a/tests/libtoolize.at
+++ b/tests/libtoolize.at
@@ -155,7 +155,7 @@ LT_AT_CHECK_LIBTOOLIZE([--copy], 0, expout, experr)
 ## Next, a second update attempt with everything now updated. ##
 ## ---------------------------------------------------------- ##
 
-AT_DATA(expout, [[]])
+: >expout
 
 AT_DATA(experr,
 [[libtoolize: `build-aux/ltmain.sh' is newer: use `--force' to overwrite
@@ -187,7 +187,7 @@ LT_AT_CHECK_LIBTOOLIZE([--copy --force], 0, expout)
 ## A final update attempt with everything previously force updated. ##
 ## ---------------------------------------------------------------- ##
 
-AT_DATA(expout, [[]])
+: >expout
 
 LT_AT_CHECK_LIBTOOLIZE([--copy], 0, expout)
 
@@ -232,7 +232,7 @@ LT_AT_CHECK_LIBTOOLIZE([--copy --install], 0, expout, 
experr)
 ## Next, a second update attempt with everything now updated. ##
 ## ---------------------------------------------------------- ##
 
-AT_DATA(expout, [[]])
+: >expout
 
 AT_DATA(experr,
 [[libtoolize: `build-aux/ltmain.sh' is newer: use `--force' to overwrite
@@ -267,7 +267,7 @@ LT_AT_CHECK_LIBTOOLIZE([--copy --force --install], 0, 
expout)
 ## A final update attempt with everything previously force updated. ##
 ## ---------------------------------------------------------------- ##
 
-AT_DATA(expout, [[]])
+: >expout
 
 LT_AT_CHECK_LIBTOOLIZE([--copy --install], 0, expout)
 
@@ -978,7 +978,7 @@ LT_AT_CHECK_LIBTOOLIZE([--copy], 0, [ignore], experr)
 LIBTOOLIZE_OPTIONS=--no-warn,--no-such-option
 export LIBTOOLIZE_OPTIONS
 
-AT_DATA(experr, [[]])
+: >experr
 
 LT_AT_CHECK_LIBTOOLIZE([--copy], 0, [ignore], experr)