TBR: travel: Add '/.jiri' to .gitignore in all repos.
TBR: travel: Add '/.jiri' to .gitignore in all repos.

Change-Id: I16915c48a2ce58c3c149700c2e9326e612607058
MultiPart: 26/28
PresubmitTest: none

vanadium/travel,vanadium/travel,vanadium/travel