IVGCVSW-3007 ArmnnConverter: Fix bug with optional --input-tensor-shape argument
IVGCVSW-3007 ArmnnConverter: Fix bug with optional --input-tensor-shape argument

Change-Id: Icae21aa39bea57fd5de4278756cc620ffe684ed7
Signed-off-by: Matthew Bentham <286076deec2404ae356dd8bc92f2f71e81044bd4@arm.com>

ARM-software/armnn,ARM-software/armnn,ARM-software/armnn