fix(MdTabs): repeat import in all.scss #TimRChen (#1848)

Author: TimRChen

src/theme/all.scss

@@ -26,7 +26,6 @@
 @import "../components/MdSwitch/theme";
 @import "../components/MdTable/theme";
 @import "../components/MdTabs/theme";
-@import "../components/MdTabs/theme";
 @import "../components/MdToolbar/theme";
 @import "../components/MdTooltip/theme";
 @import "../components/MdBadge/theme";