Changed concatenate operator to keep the "localized_label" string unmodified.

[flexoid]

Required for localizer caching.
Using << instead of + causes "required_string" merge with string in cache every request and we have labels like "Title******************" after several requests.

[justinfrench]

Weird! Either operator should be safe. Have you got any idea where the root cause is? Happy to merge this in, but would also love to plug the real cause and add spec coverage against a regression.

[flexoid]

The problem is because << changes the object on its left hand side. And string from the localized_label is the same object that stored in the cache. So, using << we change value in the cache every time we execute
((localized_label || humanized_method_name) << requirement_text).html_safe, what means every request to the page with this label.
+ solves this problem because it leaves localized_label and, respectively, value in cache, unchanged.

[justinfrench]

Merged in, thanks.

[justinfrench]

@flexoid Looks like this failed the build under 1.8.7 and ree. Can you take a look for any 1.9-specific code, check out the fail and submit a patch please? http://travis-ci.org/#!/justinfrench/formtastic/builds/730924

[justinfrench]

Looks like some 1.9-only hash syntax.

[flexoid]

Sorry, just forgot about compatibility. Thanks for fix.