Remove unnecessary return false statements

The `initialize` functions don't need to return anything, since their
returned value is never used.

Returning false is a common practice in jQuery to stop an event, but in
plain JavaScript methods it doesn't have any side effects.

app/assets/javascripts/allow_participation.js.coffee

@@ -9,4 +9,3 @@ App.AllowParticipation =
         $(this).find(".js-participation-not-allowed").hide()
         $(this).find(".js-participation-allowed").show()
     }, ".js-participation"
-    false

app/assets/javascripts/forms.js.coffee

@@ -58,4 +58,3 @@ App.Forms =
     App.Forms.toggleLink()
     App.Forms.synchronizeInputs()
     App.Forms.hideOrShowFieldsAfterSelection()
-    false

app/assets/javascripts/prevent_double_submission.js.coffee

@@ -34,5 +34,3 @@ App.PreventDoubleSubmission =
         buttons = $(this).find(":button, :submit")
         App.PreventDoubleSubmission.reset_buttons(buttons)
     )
-
-    false

app/assets/javascripts/users.js.coffee

@@ -2,4 +2,3 @@ App.Users =
 
   initialize: ->
     $(".initialjs-avatar").initial()
-    false

app/assets/javascripts/valuation_budget_investment_form.js.coffee

@@ -29,4 +29,3 @@ App.ValuationBudgetInvestmentForm =
   initialize: ->
     App.ValuationBudgetInvestmentForm.showFeasibilityFields()
     App.ValuationBudgetInvestmentForm.showFeasibilityFieldsOnChange()
-    false

app/assets/javascripts/votations.js.coffee

@@ -41,5 +41,3 @@ App.Votations =
         url = "/admin/get_options_traductions.json"
         params = { enum_type: $("#votation_type_enum_type").val() }
         $.get(url, params, (response) -> App.Votations.setTraduction response, "json")
-
-false

app/assets/javascripts/votes.js.coffee

@@ -15,4 +15,3 @@ App.Votes =
     App.Votes.hoverize "div.supports"
     App.Votes.hoverize "div.debate-questions"
     App.Votes.hoverize "div.comment-footer"
-    false

app/assets/javascripts/watch_form_changes.js.coffee

@@ -26,5 +26,3 @@ App.WatchFormChanges =
     App.WatchFormChanges.forms().each ->
       form = $(this)
       form.data("watchChanges", form.serialize())
-
-    false