[COMMIT seastar master] util: remove unused #include

[Commit Bot]

From: Kefu Chai <kefu...@scylladb.com>
Committer: Avi Kivity <a...@scylladb.com>
Branch: master

util: remove unused #include

`#include <regex>` in util/program-options.cc was added back in
735dc123f0d86822fdc8562bb3561152c3f11748, where we were using std::regex
for parsing map associations, but the function of
`parse_map_associations()` which uses std::regex was moved into
util/log.cc.

so let's remove this include from the .cc file.

Signed-off-by: Kefu Chai <kefu...@scylladb.com>

---
diff --git a/src/util/program-options.cc b/src/util/program-options.cc
--- a/src/util/program-options.cc
+++ b/src/util/program-options.cc
@@ -24,7 +24,6 @@
module;
#endif

-#include <regex>
#include <boost/any.hpp>
#include <boost/intrusive/list.hpp>
#include <boost/program_options.hpp>