debuggerd: Fix minor memory leak

free_ptrace_context(context) doesn't free(context),
which leaks the memory allocated to context.

Change-Id: Ic199b257aefc9a05ec2d902958efa8a57a601fb1
Signed-off-by: Liangtao Gao <gliangtao@gmail.com>

libcorkscrew/ptrace.c

@@ -129,6 +129,7 @@ void free_ptrace_context(ptrace_context_t* context) {
         free_ptrace_map_info_data(mi);
     }
     free_map_info_list(context->map_info_list);
+    free(context);
 }
 
 void find_symbol_ptrace(const ptrace_context_t* context,