[FIX] web: base.sass: jquery.ui widget in bootstrap's modal

Apply a z-index of 1051 (bootstrap'smodals are 1050). This fixes
an issue with the many2one hidden in a modal. Also, removed a
reference to a removed file.

addons/web/static/src/css/base.css

@@ -1847,9 +1847,6 @@
   margin-left: 10px;
   font-weight: bold;
 }
-.openerp .oe_form_field_progressbar.ui-progressbar .ui-widget-header {
-  background: #cccccc url(/web/static/lib/jquery.ui/css/smoothness/images/ui-bg_highlight-soft_75_cccccc_1x100.png) 50% 50% repeat-x;
-}
 .openerp .oe_form .oe_form_field_text {
   width: 100%;
 }
@@ -2832,6 +2829,7 @@ div.ui-widget-overlay {
   font-family: "Lucida Grande", Helvetica, Verdana, Arial, sans-serif;
   color: #4c4c4c;
   font-size: 13px;
+  z-index: 1051;
 }
 
 .ui-menu {

addons/web/static/src/css/base.sass

@@ -1553,8 +1553,6 @@ $sheet-padding: 16px
             position: absolute
             margin-left: 10px
             font-weight: bold
-        .ui-widget-header
-            background: #cccccc url(/web/static/lib/jquery.ui/css/smoothness/images/ui-bg_highlight-soft_75_cccccc_1x100.png) 50% 50% repeat-x
     // }}}
     // FormView.fields {{{
     .oe_form
@@ -2329,6 +2327,7 @@ div.ui-widget-overlay
     font-family: "Lucida Grande", Helvetica, Verdana, Arial, sans-serif
     color: #4c4c4c
     font-size: 13px
+    z-index: 1051
 
 .ui-menu
     padding: 2px 0