Fix getWsrepParameters behavior

Related: PROD-27547 (PROD:27547)

Change-Id: I961495c28a39a74f4977a5227019c6642c5de561
diff --git a/src/com/mirantis/mk/Galera.groovy b/src/com/mirantis/mk/Galera.groovy
index f3c6b7e..5178ce2 100644
--- a/src/com/mirantis/mk/Galera.groovy
+++ b/src/com/mirantis/mk/Galera.groovy
@@ -25,23 +25,18 @@
         common.prettyPrint(resultYaml)
     }
     if (parameters instanceof String) {
-        value = resultYaml[key]
-        if (value instanceof String && value.isBigDecimal()) {
-            value = value.toBigDecimal()
-        }
-        result = [key: value]
+        parameters = [parameters]
+    }
+    if (parameters == [] || parameters == ['']) {
+        result = resultYaml
     } else {
-            if (parameters == []) {
-                result = resultYaml
-            } else {
-                for (key in parameters) {
-                value = resultYaml[key]
-                if (value instanceof String && value.isBigDecimal()) {
-                    value = value.toBigDecimal()
-                }
-                result << [key: value]
-                }
+        for (key in parameters) {
+            value = resultYaml[key]
+            if (value instanceof String && value.isBigDecimal()) {
+                value = value.toBigDecimal()
             }
+            result = ["${key}": value] + result
+        }
     }
     return result
 }