deps: Fix regexp used to cleanup from fields

Credit: @iarna

Author: iarna

lib/install/deps.js

@@ -76,7 +76,7 @@ function doesChildVersionMatch (child, requested, requestor) {
     // You'll see this scenario happen with at least tags and git dependencies.
     // Some buggy clients will write spaces into the module name part of a _from.
     if (child.package._from) {
-      var fromReq = npa.resolve(moduleName(child), child.package._from.replace(new RegExp('^\s*' + moduleName(child) + '\s*@'), ''))
+      var fromReq = npa.resolve(moduleName(child), child.package._from.replace(new RegExp('^\\s*' + moduleName(child) + '\\s*@'), ''))
       if (fromReq.rawSpec === requested.rawSpec) return true
       if (fromReq.type === requested.type && fromReq.saveSpec && fromReq.saveSpec === requested.saveSpec) return true
     }