Report (and free) err_info for WTAP_ERR_DECOMPRESS.

Change-Id: I61ecc58be4b0688c43df0b0f006fb899bdc1721c
Reviewed-on: https://code.wireshark.org/review/4216
Reviewed-by: Guy Harris <guy@alum.mit.edu>

capinfos.c

@@ -1486,6 +1486,7 @@ main(int argc, char *argv[])
         case WTAP_ERR_UNSUPPORTED:
         case WTAP_ERR_UNSUPPORTED_ENCAP:
         case WTAP_ERR_BAD_FILE:
+        case WTAP_ERR_DECOMPRESS:
           fprintf(stderr, "(%s)\n", err_info);
           g_free(err_info);
           break;