The method Resource.check() is not a generator function, but it does
return a generator in most cases. Simply calling the function does not
cause the resource to actually be checked. Only in the case where the
resource did not provide a handle_check() method would it do anything at
all - and in that case it simply changes the state to CHECK_COMPLETE.
Yield the generator function so that the resource will actually be
checked if the resource type supports it.
Change-Id: I2a78b6f6235529a95838307e3d38731d31ff5c4b
Task: 37828
5c6038f7a2