T tracer tools: fix memory leaks, clang warnings

- Fix memory leaks detected by ASan
- Initialize variables that are flagged by compiler
- C struct initializer: x:y needs to be .x=y

common/utils/T/tracer/database.h

@@ -3,6 +3,7 @@
 
 /* returns an opaque pointer - truly a 'database *', see database.c */
 void *parse_database(char *filename);
+void free_database(void *database);
 void dump_database(void *database);
 void list_ids(void *database);
 void list_groups(void *database);