FS-10939 mod_cdr_mongodb: fix format truncation warnings with gcc 7 gcc 7 complains about possible format truncation:
mod_cdr_mongodb.c: In function 'my_on_reporting': mod_cdr_mongodb.c:242:45: error: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 4 [-Werror=format-truncation=] snprintf(idx_buffer, sizeof(idx_buffer), "%d", callflow_idx);
The char * idx_buffer has a size of 4 Bytes, and according to gcc's calculation it is possible that up to 11 Bytes might be copied into it via int bson_idx.
This commit adds an extra 8 Bytes to char * idx_buffer, which silences the warnings.
Signed-off-by: Sebastian Kemper <email@example.com>