Minor ui fixes for selects at issues page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/gitlab_bootstrap/common.scss

@@ -127,3 +127,8 @@ pre.well-pre {
 .dropdown-menu > li > a {
   text-shadow: none;
 }
+
+.dropdown-menu > li > a:hover,
+.dropdown-menu > li > a:focus {
+  background: #29b;
+}

app/assets/stylesheets/sections/issues.scss

@@ -77,8 +77,8 @@ input.check_all_issues {
 @media (min-width: 800px)  { .issues_filters select { width: 160px; }  }
 @media (min-width: 1200px) { .issues_filters select { width: 220px; }  }
 
-@media (min-width: 800px)  { .issues_bulk_update select { width: 120px; }  }
-@media (min-width: 1200px) { .issues_bulk_update select { width: 160px; }  }
+@media (min-width: 800px)  { .issues_bulk_update .chosen-container { min-width: 120px; }  }
+@media (min-width: 1200px) { .issues_bulk_update .chosen-container { min-width: 160px; }  }
 
 .issues-holder {
   .issues_filters {
@@ -103,3 +103,9 @@ input.check_all_issues {
 .participants {
   margin-bottom: 10px;
 }
+
+.issues_bulk_update {
+  .chosen-container {
+    text-shadow: none;
+  }
+}