curl-pkg.sh: stop creating an unused directory [ci skip]

Back in 2017/2018, we copied .html files there, but not since these
commits:

cab2610
b751deb

curl-pkg.sh

@@ -109,7 +109,7 @@
   _DST="$(pwd)/_pkg"; rm -r -f "${_DST}"
 
   mkdir -p "${_DST}/docs/examples"
-  mkdir -p "${_DST}/docs/libcurl/opts"
+  mkdir -p "${_DST}/docs/libcurl"
   mkdir -p "${_DST}/include/curl"
   mkdir -p "${_DST}/lib"
   mkdir -p "${_DST}/bin"