I think this would work the exactly opposite way. With such a "small" colony, sharing a border to a larger territory the willingness, at least in the elite, to extend would be greatly enhanced.
Depend, the 'Slap of Tunisi' destroyed the previous policy of avoid direct political/military control of any place and goes for big economic penetration and a protectorate status plus bring home how Italy was isolated on Europe and was a very big factor in her signing the Alliance with Germany and A-H.
If somehow Italy get control of Tunisia (difficult, maybe better relationships with France or/and UK) she can remain a solo player for longer or forge a different alliance altogether.
Returning at the 'No Italo-Turk war' scenario; well internally the situation will be much quiet, after the conflict there were an economic downturn that was exacerbated by the war expediture.
In case of another conflict, first the army will not be in so dire situation so it can partecipate from the beginning (and will not be commanded by Cadorna as his nomination was much due to him being untouched by the 'Lybia debacle'). Second the socialist will not be burned out by their support of the colonial war so there is the much stronger possibility that they will make a stronger united front with the goverment instead of the neutral stance of OTL (basically we don't support but neither oppose the goverment).
Optional, if no big war in Europe erupt by 1916, a second Abyssinia war can start as Ethiopia at the time was engulfed in a big civil war so things can expand.