bootlint: fix E042.

Fix the following warning from bootlint:
E042 `.form-control` cannot be used on non-textual `<input>`s, such as those whose `type` is:
`file`, `checkbox`, `radio`, `range`, `button`

@see https://github.com/twbs/bootlint/wiki/E042

Last part of fix for #278

Author: php-coder

src/main/webapp/WEB-INF/views/series/add.html

@@ -201,7 +201,7 @@ <h3 th:text="${#strings.capitalize(add_series)}">
 								<span id="image.required" class="required_field">*</span>
 							</label>
 							<div class="col-sm-7">
-								<input type="file" id="image" class="form-control" style="box-shadow: none; border: 0px;" required="required" accept="image/png,image/jpeg" th:field="*{image}" />
+								<input type="file" id="image" style="box-shadow: none; border: 0px;" required="required" accept="image/png,image/jpeg" th:field="*{image}" />
 								<small togglz:active="ADD_ADDITIONAL_IMAGES_TO_SERIES" sec:authorize="hasAuthority('ADD_IMAGES_TO_SERIES')">
 									<span class="hint-block" th:text="#{t_add_more_images_hint}">
 										You will be able to add additional images on the series page

src/main/webapp/WEB-INF/views/series/info.html

@@ -293,7 +293,7 @@
 								<div class="col-sm-6 col-sm-offset-3">
 									<form method="post" class="form-horizontal" enctype="multipart/form-data" th:action="@{${ADD_IMAGE_SERIES_PAGE}(id=${series.id})}" th:object="${addImageForm}">
 										<div class="form-group" th:classappend="${#fields.hasErrors('image') ? 'has-error' : ''}">
-											<input type="file" id="image" class="form-control" style="box-shadow: none; border: 0px;" required="required" accept="image/png,image/jpeg" th:field="*{image}" />
+											<input type="file" id="image" style="box-shadow: none; border: 0px;" required="required" accept="image/png,image/jpeg" th:field="*{image}" />
 											<span id="image.errors" class="help-block" th:if="${#fields.hasErrors('image')}" th:each="error : ${#fields.errors('image')}" th:text="${error}"></span>
 										</div>
 										<div class="from-group-sm">