fb: fix reconstruct statusbar illegal argument exception

Finally I got a logcat what is happening in rare cases. If the reconstruct
happens during a notification ticker was send it returns a negative
width value for the static layout and systemUI crashes.

E/AndroidRuntime(  970): java.lang.IllegalArgumentException: Layout: -23 < 0
E/AndroidRuntime(  970):        at android.text.Layout.<init>(Layout.java:138)
E/AndroidRuntime(  970):        at android.text.StaticLayout.<init>(StaticLayout.java:104)
E/AndroidRuntime(  970):        at android.text.StaticLayout.<init>(StaticLayout.java:90)
E/AndroidRuntime(  970):        at android.text.StaticLayout.<init>(StaticLayout.java:68)
E/AndroidRuntime(  970):        at android.text.StaticLayout.<init>(StaticLayout.java:48)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.phone.Ticker$Segment.getLayout(Ticker.java:72)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.phone.Ticker$Segment.getText(Ticker.java:91)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.phone.Ticker.addEntry(Ticker.java:226)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.phone.PhoneStatusBar.tick(PhoneStatusBar.java:2862)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.phone.PhoneStatusBar.addNotification(PhoneStatusBar.java:1432)
E/AndroidRuntime(  970):        at com.android.systemui.statusbar.CommandQueue$H.handleMessage(CommandQueue.java:322)

to avoid this check before a new StaticLayout is constructed if the width is < 0 and if this
is the case abort the operation. This is in this case a legit way due that the notification
gets reconstructed during this process later so or so

Change-Id: I6ed68bbb9226101d3573f3d76deb793ddae69627