The fru edit command may need to consider if that section is not present

[andrew8325]

Describe the bug
Hi, recently I found when using command ipmitool fru edit <fruid> field <section> <index> <string> to modify the fru Chassis/Board/Product section, the fru edit command may also update the MultiRecord area offset even if the MultiRecord is not present (offset is 00).

IPMITOOL Version

$ ipmitool -V
ipmitool version 1.8.19.1.g4519b4b

To Reproduce
Steps to reproduce the behavior:

1. Modify the FRU field by ipmitool

root:~$ ipmitool fru edit 0 field p 1 ABC
String size are not equal, resizing fru to fit new string
Read All FRU area
Fru Size       : 512 bytes
Copy to new FRU
Section Length: 72
Padding Length: 1
NumByte Change: 2
Start SecChnge: c1
End SecChnge  : 36
Start Section : 1
End Sec wo Pad: c1
End Section   : 81
New Padding Length: -1
change_size_by_8: 1
New Padding Length: 7
change_size_by_8: 1
header.offset.board: 7
Change multi offset from 0 to 1
Moving Remaining Bytes (Multi-Rec , etc..), from 200 to 208
Updating Field : ' ' with 'ABC' ... (Length from '193' to '195')
Copying remaining of sections: 60 
Calculate New Checksum: ffffffc5
Writing new FRU.
Done.

2. The MultiRecord offset in those the common header would be modified to 1 according to log Change multi offset from 0 to 1

Expected behavior
If the MultiRecord is not present, the offset of this section should remain 00.

Additional context