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>
diff --git a/libcorkscrew/ptrace.c b/libcorkscrew/ptrace.c
index 6496d5e..776ef69 100644
--- a/libcorkscrew/ptrace.c
+++ b/libcorkscrew/ptrace.c
@@ -129,6 +129,7 @@
         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,