disable 'offline' option in install wizard, because it is not implemented

gui/qt/installwizard.py

@@ -194,7 +194,7 @@ class InstallWizard(QDialog):
         grid = QGridLayout()
         grid.setSpacing(5)
 
-        label = QLabel(_("Electrum communicates with Electrum servers to get information about your transactions and addresses. The servers all fulfil the same purpose only differing in hardware. In most cases you simply want to let Electrum pick one at random if you have a preference though feel free to select a server manually or stay offline.") + "\n\n" \
+        label = QLabel(_("Electrum communicates with remote servers to get information about your transactions and addresses. The servers all fulfil the same purpose only differing in hardware. In most cases you simply want to let Electrum pick one at random if you have a preference though feel free to select a server manually.") + "\n\n" \
                       + _("How do you want to connect to a server: "))
         label.setWordWrap(True)
         grid.addWidget(label, 0, 0)
@@ -208,12 +208,12 @@ class InstallWizard(QDialog):
         b2 = QRadioButton(gb)
         b2.setText(_("Select server manually"))
 
-        b3 = QRadioButton(gb)
-        b3.setText(_("Stay offline"))
+        #b3 = QRadioButton(gb)
+        #b3.setText(_("Stay offline"))
 
         grid.addWidget(b1,1,0)
         grid.addWidget(b2,2,0)
-        grid.addWidget(b3,3,0)
+        #grid.addWidget(b3,3,0)
 
         vbox = QVBoxLayout(self)
         vbox.addLayout(grid)