update(lib_image):Adding LIB_IMAGE ENV in node cpu/memory hog experiment (#204)

Signed-off-by: shubhamchaudhary <shubham.chaudhary@mayadata.io>

charts/generic/disk-fill/engine.yaml

@@ -28,4 +28,5 @@ spec:
               value: '80'
               
             - name: TARGET_CONTAINER
-              value: 'nginx'
+              value: 'nginx'
+              

charts/generic/disk-fill/experiment.yaml

@@ -54,6 +54,11 @@ spec:
     # Period to wait before injection of chaos in sec
     - name: RAMP_TIME
       value: ''
+
+    # Provide the LIB here
+    # Only litmus supported
+    - name: LIB
+      value: 'litmus'
       
     labels:
       name: disk-fill