Drop :export metadata from fource-update-all function

There doesn't seem to be any reason to export this function, and nothing
else is exported. Exporting function also prevents DCE, though in this
case this function probably only adds few bytes as the code include
is anyway used by Reagent applications.

CHANGELOG.md

@@ -16,6 +16,7 @@ to normalize and combine `:class` values (similar to `classnames` JS library)
 uses correct Object interop forms, allowing use of ClojureScript `:checked-arrays :warn` option. ([#325](https://github.com/reagent-project/reagent/issues/325))
 - Deprecated `reagent.interop` namespace
     - It is better to use proper object interop forms or `goog.object` functions instead.
+- Drop `:export` metadata from `force-update-all` function
 
 ## 0.8.1 (2018-05-15)
 

src/reagent/core.cljs

@@ -87,7 +87,7 @@
 (def as-component as-element)
 (def render-component render)
 
-(defn ^:export force-update-all
+(defn force-update-all
   "Force re-rendering of all mounted Reagent components. This is
   probably only useful in a development environment, when you want to
   update components in response to some dynamic changes to code.