configure.ac: remove bad macro that overwrote automake internals

In the original port to autotools, a "ts" macro was defined in m4. This
meant any whole word "ts" in configure.ac or any included *.m4 file got
replaced with an integer plus a newline char. Automake does this
sometimes, such as in:

```
rm -f conftest.ts?
```

which was translated to:

```
rm -f conftest.20250527230813
?
```

At the time it was used to replace, on a later line,
```
BUILD_TS=ts
```

But this was removed as "unused" in 2017. It was always the wrong way to
define it and is now inert except for breaking automake. Get rid of it
fully.

Fixes: 597216e
Signed-off-by: Eli Schwartz <[email protected]>

Author: eli-schwartz

configure.ac

@@ -14,8 +14,6 @@ define([ucx_ver_minor], 20) # Minor version. Increased for each release.
 define([ucx_ver_patch], 0)  # Patch version. Increased for a bugfix release.
 define([ucx_ver_extra], )   # Extra version string. Empty for a general release.
 
-define([ts], esyscmd([sh -c "date +%Y%m%d%H%M%S"]))
-
 # This is the API version (see libtool library versioning)
 # http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
 # current:rev:age