Complie OpenDPI failed if IPOQUE_ENABLE_DEBUG_MESSAGES is enabled

[Kenny]

Hi, guys
If IPOQUE_ENABLE_DEBUG_MESSAGES is enabled it will fail to compile
OpenDPI for the following error:

ipq_main.h: In function 'ipq_get_ip_string':
ipq_main.h:420: error: 'struct ipoque_detection_module_struct' has no
member named 'ip_string'
ipq_main.h:420: error: 'IPOQUE_IP_STRING_SIZE' undeclared (first use
in this function)
ipq_main.h:420: error: (Each undeclared identifier is reported only
once
ipq_main.h:420: error: for each function it appears in.)
ipq_main.h:421: error: 'struct ipoque_detection_module_struct' has no
member named 'ip_string'

From the source code, IPOQUE_IP_STRING_SIZE DOES have no definition
and also ip_string member doesn't exist in struct
ipoque_detection_module_struct.

Did we miss something to commit?
Thanks.

Kenny