make sure only one record field has pointer to the master field; fix code indents to 4 spaces

src/database/pvRecord.cpp

@@ -498,8 +498,11 @@ void PVRecordStructure::init()
                 // Find master field
                 PVRecordStructurePtr p = pvRecordField->parent.lock();
                 while (p) {
+                    PVRecordStructurePtr p2 = p->parent.lock();
+                    if (!p2) {
                         pvRecordField->master = p;
-                     p = p->parent.lock();
+                    }
+                    p = p2;
                 }
             }
         }