fixing tests and indentation errors

fixed rename and rmdir tests with correct if statements
and removed tabs from test_fallocate

Change-Id: I02edd7511ba134395cba94b8f2d32b73dd936a0f
Signed-off-by: Thiago da Silva <thiago@redhat.com>
adding error handling to api calls

Added error handling to all api calls.
On error from gfapi, a OSError or IOError exception
is raised

Change-Id: I9944ae6796da49e7678089c60138a67dff30887e
Signed-off-by: Thiago da Silva <thiago@redhat.com>
make code pep8 compliant

all changes in this patch were made to make the code
pep8 compliant

Change-Id: Ie05e370126ad4f48c4a4891c44b4440628fcb775
Signed-off-by: Thiago da Silva <thiago@redhat.com>
unit tests

added unit tests for existing methods

Change-Id: Iecd31bc1dea44ea38168120bd05ca505c4ff5c59
Signed-off-by: Thiago da Silva <thiago@redhat.com>