By Bill Graveland More than 100 Sikhs waved blue and yellow Khalistan flags and held up posters Monday condemning Indian Prime Minister Narendra Modi ahead of his visit to the G7 leaders’ summit. One poster depicted the Indian leader handcuffed in a prison jumpsuit, and another showed him locked up behind bars with the message: “I killed Nijjar, a Canadian citizen.” Modi was expected to arrive in Calgary later Monday. The G7 is being held west of the city in a wilderness retreat in Kananaskis. There has been outrage since Prime Minister Mark Carney invited Modi as a guest at the G7 gathering. Bakshish Singh Sandhu, co-founder of the advocacy group Sikhs for Justice, said Modi’s appearance in Canada is also an opportunity to shine a light on what he…