gitignore: remove MANIFEST.MF
gitignore: remove MANIFEST.MF

Now MANIFEST.MF is created under target directory.
There is no need to ignore MANIFEST.MF and MANIFEST that is not under
target/ directory should not be ignored.

Change-Id: If87003eb0fa38e78164df6ee36a9ed4471c35fcf
Signed-off-by: Isaku Yamahata <87b7f730b993ec3947ada6404f19ac98e56bb574@intel.com>

opendaylight/neutron