Fix inconsistency in the header of issue and merge request pages

closes #13550 

# For Issue Page

### Before
![Screen_Shot_2016-03-17_at_8.46.59_PM](/uploads/ede7f2b98395362ae87e6258cc10520a/Screen_Shot_2016-03-17_at_8.46.59_PM.png)

### After
![Screen_Shot_2016-03-17_at_8.48.56_PM](/uploads/da7adf17cb397ddc0677a6a5e8033b8e/Screen_Shot_2016-03-17_at_8.48.56_PM.png)

# For Merge request Page

### Before
![Screen_Shot_2016-03-17_at_8.45.45_PM](/uploads/10137827c05c8166a0aa429687e50d1b/Screen_Shot_2016-03-17_at_8.45.45_PM.png)

### After
![Screen_Shot_2016-03-17_at_8.45.01_PM](/uploads/92151c03cfe29b71090a1e0ad31abd6e/Screen_Shot_2016-03-17_at_8.45.01_PM.png)


See merge request !3279