fix missing new lines in mvar_spec.rb

Author: lionelperrin

spec/concurrent/mvar_spec.rb

@@ -69,25 +69,30 @@ def dereferenceable_subject(value, opts = {})
       end
 
       context 'when a block is given' do
+
         it 'yields current value to the block and puts back value' do
           m = MVar.new(14)
           expect { |b| m.take(&b) }.to yield_with_args(14)
           expect(m.take).to eq(14)
         end
+
         it 'puts back value even if an exception is raised' do
           m = MVar.new(14)
           expect { m.take { fail 'boom!' } }.to raise_error('boom!')
           expect(m.take).to eq(14)
         end
+
         it 'returns the returned value of the block' do
           m = MVar.new(14)
           expect(m.take{2}).to eq(2)
           expect(m.take).to eq(14)
         end
+
         it 'returns TIMEOUT on timeout on an empty MVar' do
           m = MVar.new
           expect(m.take(0.1){}).to eq MVar::TIMEOUT
         end
+
       end
 
     end