I am not an immigration consultant, but I once was. I gave up my license because my other area of business was too busy to do immigration as well. I rec'd 100% on the module involving inadmissibility...but that was about 7 years ago. Things could have changed.
My specialty is in pardons & waivers. From what I know for sure, the conditional discharge goes away automatically after 3 years. And, if a person was convicted in Canada only, they can overcome inadmissibility in Canada once their pardon is granted. HOWEVER, if they were ordered removed or deported, they also have to come over removal or deportation with a Criminal Rehabilitation Application.
If no removal or deportation, they are no longer inadmissible if (a) conditional discharge is purged ie. Aug 2014; or (b) they have a conviction which has since been pardoned...and they do not have to apply for criminal rehabilitation.
Inadmissibility is based upon conviction or commmission of an offence. If you read the criminal code of canada, a conditional discharge is given when there has been an admission or finding of guilt but it is determined not to be in society's best interest to convict. Therefore, though technically NOT a conviction...it is still an admission of guilty. I take this to mean it is proof of commission of an offence.
Go to CIC website and search for "Application for Criminal Rehabilitation" for more information on inadmissibility. AND, if you want to get really detailed, search IRPA which stands for Immigration and Refugee Protection Act for laws in Canada on the matter.