pmdasmart: fix logic error causing nvme-cli check to be ignored

The fetch logic for NVME metrics in the SMART PMDA check for
command-not-found on the first invocation (of several) - but
continues to issue the following commands with no checks.  A
fail-fast/short-circuit path is added to prevent this and in
so doing solve a QA failure in qa/1397.

src/pmdas/smart/smart_stats.c

@@ -715,7 +715,7 @@ nvme_device_refresh_data(const char *name, struct nvme_device_info *nvme_device_
                                 // Make use of redirected stderr to stdout to check if nvme-cli is
                                 // installed and and disable if not
                                nvmecli_support = 0;
-                               continue;
+                               break;
                         }
 
                         if (strstr(buffer, "Power State")) {
@@ -726,6 +726,10 @@ nvme_device_refresh_data(const char *name, struct nvme_device_info *nvme_device_
 	        }
 	        pclose(pf);
 
+		/* Short-circuit here, only the first invocation checks for nvme-cli */
+		if (!nvmecli_support)
+			return 0;
+
                 /*
                   smart.nvme_info.apste_state
                 */