spec_helper: pass in already obtained line (#60)

The tests are quite slow, and I have the feeling that most comes from
the helpers, and more importantly not reusing the Vim instance (because
of the lockup issue).

Author: blueyed

spec/spec_helper.rb

@@ -38,7 +38,7 @@ def previous_indent
     def proposed_indent
       line = vim.echo("line('.')")
       col = vim.echo("col('.')")
-      indent_value = vim.echo("GetPythonPEPIndent(line('.'))").to_i
+      indent_value = vim.echo("GetPythonPEPIndent(#{line})").to_i
       vim.command("call cursor(#{line}, #{col})")
       return indent_value
     end