§ 87. Prohibition against disqualification on account of age or disability. A veteran or disabled veteran shall not be disqualified from holding any position in the civil service on account of age, except for positions for which age limitations are specifically authorized or prescribed by law, provided such age does not render him incompetent to perform the duties of the position applied for. A disabled veteran shall not be disqualified from holding any position in the civil service by reason of a war-incurred disability, provided such disability does not render him incompetent to perform the duties of the position applied for.