TESTS: Add different log levels to the TUR test test suite and see how it looks

Add different log levels and update the TUR testsute.
Update the helper for testunitready() so that it
* prints FAILURE messages for normal and verbose levels
* prints selfdocumenting messages for which SCSI command it sends and the expected result for the verbose level

test-tool/iscsi-support.h

@@ -29,6 +29,11 @@ extern const char *initiatorname1;
 extern const char *initiatorname2;
 extern const char *tgt_url;
 
+extern int loglevel;
+#define LOG_SILENT  0
+#define LOG_NORMAL  1
+#define LOG_VERBOSE 2
+
 extern uint32_t block_size;
 extern uint64_t num_blocks;
 extern int lbpme;