I think that the Qatari government has a lot of reason to cover up an explosion primarily because they want to be seen as a safe place in the middle east so investors and tourists don't get scared off. There is no real way to know if they did or not.
I think any time a major terrorist event occurs there is great confusion on what exactly happened and sometimes people mistake the initial confusion for the Government trying to cover it up, the Government knows the media will find out the truth anyways so I find it highly unlikely the Qatari Government is actively trying to cover up the truth.
Just as the US government was accused of being behind the 9/11 attacks, conspiracy theorists will often try to seek out as many possible explanations as they can to come up with alternate explanations. It will probably never be known, barring some substantial leak or giving out of information on the subject.
I do not believe Qatar government is covering up the truth behind a recent explosion at a restaurant. The explosion was supposedly the result of a gas tank exploding, which would cause the damage detailed in the articles found on-line. Rather it was an accident or on purpose it obviously unknown at this time, but accidents do still happen.
I do not think that the Qatari government is covering up the truth beind a recent explosion at a restaurant. I think that there isn't really any evidence to think that they are doing anything suspicious. Until more evidence can be found, they should not be criticized with how they're dealing with the situation.