Issue Description:
When uploading a file to switch, we will find the free space is not enough. In this case we have to delete some file.

<S5700> delete s5720si-v200r019c00spc200.cc

When checking the available space, the space remains the same. The question is where did this file we "deleted" go to?

Ps: checking the available space = (87,476 KB free)
Solution:
When deletinh a file by this command:
<S5700> delete s5720si-v200r019c00spc200.cc
Actually this file will be moved into recycle bin instead of erasering from Flash.
If we run command:
<S5700> dir /all
Directory of flash:/

To eraser them from Flash totally, there are 2 ways:
1. when delete the file, use parameter /unreserved , so that the file will not be moved to recycle bin.
<S5700>delete /unreserved s5720si-v200r019c00spc200.cc
2. Use this command to remove the files in recycle bin:
<S5700> reset recycle-bin s5720si-v200r019c00spc200.cc

Then the files will be erasered from Flash and the space will be released.

Ps: checking the available space = (153,064 KB free)


Y'W