auth: Return a string_view from authenticator::qualified_java_name

This gives more flexibility to the implementations as they now don't
need to construct a sstring.

Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>

auth/allow_all_authenticator.hh

@@ -52,7 +52,7 @@ public:
         return make_ready_future<>();
     }
 
-    virtual const sstring& qualified_java_name() const override {
+    virtual std::string_view qualified_java_name() const override {
         return allow_all_authenticator_name();
     }
 

auth/authenticator.hh

@@ -96,7 +96,7 @@ public:
     ///
     /// A fully-qualified (class with package) Java-like name for this implementation.
     ///
-    virtual const sstring& qualified_java_name() const = 0;
+    virtual std::string_view qualified_java_name() const = 0;
 
     virtual bool require_authentication() const = 0;
 

auth/password_authenticator.cc

@@ -197,7 +197,7 @@ db::consistency_level password_authenticator::consistency_for_user(std::string_v
     return db::consistency_level::LOCAL_ONE;
 }
 
-const sstring& password_authenticator::qualified_java_name() const {
+std::string_view password_authenticator::qualified_java_name() const {
     return password_authenticator_name();
 }
 

auth/password_authenticator.hh

@@ -71,7 +71,7 @@ public:
 
     virtual future<> stop() override;
 
-    virtual const sstring& qualified_java_name() const override;
+    virtual std::string_view qualified_java_name() const override;
 
     virtual bool require_authentication() const override;
 

auth/transitional.cc

@@ -82,7 +82,7 @@ public:
         return _authenticator->stop();
     }
 
-    virtual const sstring& qualified_java_name() const override {
+    virtual std::string_view qualified_java_name() const override {
         return transitional_authenticator_name();
     }