Fix a possible bug introduced in 0717257d.
Fix a possible bug introduced in 0717257d.

Functions that call Group::tagCloudData() expect an Exception on error,
not a Boolean false return value. Fix the method to again throw the
Exception. Leave the try...catch block in it to make the thrown
Exception obvious.

foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm,foocorp/gnu-fm