Removing bind so this works with externally defined replacements

[samuelmburu]

I have a shared list of replacements that I share across build systems, by removing the bind(this) the replacements work otherwise I get the following error:

Module build failed: TypeError: repl.replacement.bind is not a function
    at Object.<anonymous> (/Users/samuelmburu/workspace/productivity/survata-com/node_modules/string-replace-webpack-plugin/loader.js:20:72)
    at Array.forEach (<anonymous>)
    at Object.module.exports (/Users/samuelmburu/workspace/productivity/survata-com/node_modules/string-replace-webpack-plugin/loader.js:19:34)