Remove space in lambda expression revert support for ruby 1.9.3

Space between `->` and `(_)` causes Syntax error in ruby version 1.9.3. 
Remove this space resolve problem.

```
[1] pry(main)> RUBY_VERSION
=> "1.9.3"
[2] pry(main)> -> (_) { puts "hello" }
SyntaxError: unexpected tLAMBEG, expecting $end
-> (_) { puts "hello" }
        ^
[2] pry(main)> ->(_) { puts "hello" }
=> #<Proc:0x000000013952a0@(pry):2 (lambda)>
```