Don't (always) leak the file descriptor.

It's still very much possible to leak the descriptor (when an exception occurs
somewhere in between or anything else goes wrong). So maybe the whole thing
should be redesigned to be independent of files.

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleIoThread.java

@@ -419,6 +419,11 @@ public class PebbleIoThread extends GBDeviceIoThread {
 
         mPBWReader = null;
         mIsInstalling = false;
+        try {
+            mZis.close();
+        } catch (IOException e) {
+            // ignore
+        }
         mZis = null;
         mAppInstallToken = -1;
         mInstallSlot = -2;