bootstrap: Remove CSS for "submit" type inputs.

We use "submit" type inputs in dev login page. Only "cursor"
CSS was applied to those elements from bootstrap and this
commit adds it to those elements in portico_signin.css and
removes the CSS in bootstrap.css and bootstrap-btn.css.

web/third/bootstrap/css/bootstrap-btn.css

@@ -358,6 +358,3 @@ fieldset[disabled] .btn-link:focus {
 .btn-block + .btn-block {
   margin-top: 5px;
 }
-input[type="submit"].btn-block {
-  width: 100%;
-}

web/third/bootstrap/css/bootstrap.css

@@ -62,14 +62,12 @@ input::-moz-focus-inner {
   padding: 0;
   border: 0;
 }
-button,
-input[type="submit"] {
+button {
   -webkit-appearance: button;
   cursor: pointer;
 }
 label,
-button,
-input[type="submit"] {
+button {
   cursor: pointer;
 }
 body {
@@ -496,8 +494,7 @@ input[type="url"]:focus {
   box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(82,168,236,.6);
 }
 input[type="file"],
-input[type="image"],
-input[type="submit"] {
+input[type="image"] {
   width: auto;
 }
 input[type="file"] {