Remove string name with duplicate value

Closes issue pockethub#85

Author: kevinsawicki

app/res/values/strings.xml

@@ -169,7 +169,6 @@
     <string name="invalid_login_or_password">Please enter a valid login &amp; password</string>
     <string name="invalid_password">Please enter a valid password.</string>
     <string name="password">Password</string>
-    <string name="log_in">Log in</string>
     <string name="login_or_email">Login or Email</string>
     <string name="followers">Followers</string>
     <string name="following">Following</string>