enip: fix scan-build warnings

detect-cipservice.c:161:29: warning: Assigned value is garbage or undefined
    cipserviced->cipservice = input[0];
                            ^ ~~~~~~~~
detect-cipservice.c:162:27: warning: Assigned value is garbage or undefined
    cipserviced->cipclass = input[1];
                          ^ ~~~~~~~~
detect-cipservice.c:163:31: warning: Assigned value is garbage or undefined
    cipserviced->cipattribute = input[2];
                              ^ ~~~~~~~~
3 warnings generated.

src/detect-cipservice.c

@@ -101,7 +101,7 @@ static DetectCipServiceData *DetectCipServiceParse(const char *rulestrc)
     char* token;
     char *save;
     int var;
-    int input[3];
+    int input[3] = { 0, 0, 0 };
     int i = 0;
 
     token = strtok_r(rulestr, delims, &save);
@@ -158,6 +158,11 @@ static DetectCipServiceData *DetectCipServiceParse(const char *rulestrc)
         token = strtok_r(NULL, delims, &save);
     }
 
+    if (i == 0) {
+        SCLogError(SC_ERR_INVALID_SIGNATURE, "no tokens found");
+        goto error;
+    }
+
     cipserviced->cipservice = input[0];
     cipserviced->cipclass = input[1];
     cipserviced->cipattribute = input[2];