spicy_add_analyzer: Do not use SCRIPTS

The SCRIPTS parameter for spicy_add_analyzer() is not functional, so rendering
it into CMakeLists.txt is confusing [1]. Remove it.

These scripts are installed via zkg.meta's script_dir here in the template.

[1] zeek/cmake#97

features/spicy-protocol-analyzer/analyzer/CMakeLists.txt

@@ -2,5 +2,4 @@ spicy_add_analyzer(
     NAME @ANALYZER@
     PACKAGE_NAME @NAME@
     SOURCES @[email protected] @[email protected] zeek_@[email protected]
-    SCRIPTS __load__.zeek main.zeek dpd.sig
 )