LU-18798 mdd: Exclude quotes from user.job xattr.

LU-18798 mdd: Exclude quotes from user.job xattr.

Exclude quotes around the jobid string when saving it into the
user.job xattr. Adjusted the mdd_buf_get_const() call to use
jobid + 1 as the starting point and jobid_len - 2 as the length
when quotes are detected.

Test-Parameters: trivial
Signed-off-by: Aryan Gupta <argupta@ddn.com>
Change-Id: I4dcf7012572de71a0bb64f3376a9f2d8544c0684
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58943
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>