Fix typo in data_file generator code

The file to generate is `server10_int3-bs.pem`, not
`server10-bs_int3-bs.pem`.
diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index ff89476..be08580 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -153,7 +153,7 @@
 all_final += test-int-ca3-badsign.crt
 server10_int3-bs.pem: server10.crt test-int-ca3-badsign.crt
 	cat server10.crt test-int-ca3-badsign.crt > $@
-all_final += server10-bs_int3-bs.pem
+all_final += server10_int3-bs.pem
 
 rsa_pkcs1_2048_public.pem: server8.key
 	$(OPENSSL)  rsa -in $< -outform PEM -RSAPublicKey_out -out $@