[sr-dev] compiler warnings in master's siptrace

[Juha Heinanen]

CC (gcc) [M siptrace.so]		siptrace.o
siptrace.c: In function 'trace_onreply_out':
siptrace.c:1227:6: warning: unused variable 'len' [-Wunused-variable]
  int len;
      ^~~
siptrace.c: In function 'siptrace_net_data_recv':
siptrace.c:1477:1: warning: label 'error' defined but not used [-Wunused-label]
 error:
 ^~~~~
siptrace.c:1436:6: warning: unused variable 'olen' [-Wunused-variable]
  int olen;
      ^~~~
siptrace.c:1435:8: warning: unused variable 'cp' [-Wunused-variable]
  char *cp;
        ^~
siptrace.c: In function 'siptrace_net_data_send':
siptrace.c:1491:6: warning: unused variable 'olen' [-Wunused-variable]
  int olen;
      ^~~~
siptrace.c:1490:8: warning: unused variable 'p0' [-Wunused-variable]
  char *p0;
        ^~
siptrace.c:1489:8: warning: unused variable 'cp' [-Wunused-variable]
  char *cp;
        ^~