build: remove obsolete virtual specifier

Author: darwin67

cmake/mode.common.cmake

@@ -6,7 +6,6 @@ set(disabled_warnings
   overloaded-virtual
   unsupported-friend
   enum-constexpr-conversion
-  unnecessary-virtual-specifier
   unused-parameter)
 include(CheckCXXCompilerFlag)
 foreach(warning ${disabled_warnings})

configure.py

@@ -1548,7 +1548,6 @@ def get_warning_options(cxx):
         '-Wno-unsupported-friend',
         '-Wno-missing-field-initializers',
         '-Wno-deprecated-copy',
-        '-Wno-unnecessary-virtual-specifier',
         # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728
         '-Wno-psabi',
         '-Wno-enum-constexpr-conversion',

cql3/column_identifier.hh

@@ -82,7 +82,7 @@ public:
 
     const sstring& text() const;
 
-    virtual sstring to_string() const;
+    sstring to_string() const;
     sstring to_cql_string() const;
 
     friend std::hash<column_identifier_raw>;