Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: JoaoJandre

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStorageProcessor.java

@@ -2093,7 +2093,7 @@ protected void rebaseSnapshot(SnapshotObjectTO snapshotObjectTO, KVMStoragePool
             QemuImg qemuImg = new QemuImg(wait);
             qemuImg.rebase(snapshotFile, parentSnapshotFile, PhysicalDiskFormat.QCOW2.toString(), false);
         } catch (LibvirtException | QemuImgException e) {
-            if (!e.getMessage().contains("Is another process using the image")) {
+            if (!StringUtils.contains(e.getMessage(), "Is another process using the image")) {
                 logger.error("Exception while rebasing incremental snapshot [{}] due to: [{}].", snapshotName, e.getMessage(), e);
                 throw new CloudRuntimeException(e);
             }
@@ -2109,7 +2109,9 @@ private void retryRebase(String snapshotName, int wait, Exception e, QemuImgFile
             qemuImg.rebase(snapshotFile, parentSnapshotFile, PhysicalDiskFormat.QCOW2.toString(), false);
         } catch (LibvirtException | QemuImgException | InterruptedException ex) {
             logger.error("Unable to rebase snapshot [{}].", snapshotName, ex);
-            throw new CloudRuntimeException(e);
+            CloudRuntimeException cre = new CloudRuntimeException(ex);
+            cre.addSuppressed(e);
+            throw cre;
         }
     }