PY-2019.3.1 <prape@r421-69 Update colors.scheme.xml, laf.xml

_linux/laf.xml

 <application>
   <component name="LafManager">
-    <laf class-name="com.intellij.ide.ui.laf.IntelliJLaf" />
+    <laf class-name="com.intellij.ide.ui.laf.darcula.DarculaLaf" />
   </component>
 </application>
\ No newline at end of file

colors.scheme.xml

 <application>
   <component name="EditorColorsManagerImpl">
-    <global_color_scheme name="_@user_Default" />
+    <global_color_scheme name="Darcula" />
   </component>
 </application>
\ No newline at end of file