support/testing: TestLibCurl: replace thttpd by Busybox's httpd server

In order to remove thttpd package from Buildroot, we have to replace it
from TestLibCurl.

Busybox's httpd server doesn't report server identification, update
TestLibCurl accordingly.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/11042294712

Cc: Julien Olivain <ju.o@free.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>

support/testing/tests/package/test_libcurl.py

@@ -8,7 +8,7 @@ class TestLibCurl(infra.basetest.BRTest):
         """
         BR2_PACKAGE_LIBCURL=y
         BR2_PACKAGE_LIBCURL_CURL=y
-        BR2_PACKAGE_THTTPD=y
+        BR2_PACKAGE_BUSYBOX_HTTPD=y
         BR2_TARGET_ROOTFS_CPIO=y
         # BR2_TARGET_ROOTFS_TAR is not set
         """
@@ -45,11 +45,9 @@ class TestLibCurl(infra.basetest.BRTest):
         self.assertEqual(out[0], msg)
 
         # We download one last time, showing the server response. We
-        # check we can see the OK status and our thttpd server
-        # identification.
+        # check we can see the OK status.
         cmd = f"curl --no-progress-meter --dump-header - -o /dev/null {url}"
         out, ret = self.emulator.run(cmd)
         self.assertEqual(ret, 0)
         out_str = "\n".join(out)
         self.assertIn("HTTP/1.1 200 OK", out_str)
-        self.assertIn("Server: thttpd/", out_str)