Changed modifier on approveForPool and unapproveForPool

from `onlyMainAdmin` to `onlyPoolController`.

contracts/terminus/controller/TerminusControllerFacet.sol

@@ -202,14 +202,14 @@ contract TerminusControllerFacet is TerminusPermissions, TokenDrainerFacet {
 
     function approveForPool(uint256 poolID, address operator)
         external
-        onlyMainAdmin
+        onlyPoolController(poolID)
     {
         terminusContract().approveForPool(poolID, operator);
     }
 
     function unapproveForPool(uint256 poolID, address operator)
         external
-        onlyMainAdmin
+        onlyPoolController(poolID)
     {
         terminusContract().unapproveForPool(poolID, operator);
     }