Removing mines on your side of the border is the way to open the gates to invade the other guy. If you are intending to stay put, you would leave the mines for protection. By taking them out, you lower your defenses a bit to enable you to invade the other guy at a moments notice.
This is a clear sign that Syria intends to invade Israel, or is threatining to do so.
It is also a sign of a broad based assault. If you are going for a narrow front, you keep the mines in place (assuming you have a known path through them). That way "just in case" your rear areas are protected.
Or, if Syria believes strongly that Israel will not invade Syria, then they can clear the mines as a provocation, as subterfuge, or to enable insurgents to try to sneak through or some other reason of brinksmanship or tactics.
It could be that Syria wants Israel to invade, either as a trap or as a form of coup. What if the second tier of Syrian command wants to see the Syrian regime tumble or pulled out of Iran's grasp, and the only way to effect that is to get IDF backup?
Think of it as the Klingons removing their cloaking device so they can fire thyeir phazers at the Star Trek Enterprise.