Fixes crash occuring when restarting a finished session

app/src/main/java/net/pokeranalytics/android/model/realm/Session.kt

@@ -321,8 +321,8 @@ open class Session : RealmObject(), Savable, Editable, StaticRowRepresentableDat
 			val computableResult = realm.createObject(ComputableResult::class.java)
 			computableResult.session = this
 		}  // if a ComputableResult exists and the session is not completed, delete it
-		else if (this.startDate == null || this.endDate == null) {
-			this.computableResult?.deleteFromRealm()
+		else if ((this.startDate == null || this.endDate == null) && this.computableResult != null && this.computableResult.isValid) {
+			this.computableResult.deleteFromRealm()
 		}
 
 		// Update the ComputableResult
@@ -441,9 +441,9 @@ open class Session : RealmObject(), Savable, Editable, StaticRowRepresentableDat
 	 */
 	fun restart() {
 		realm.executeTransaction {
-//			this.timeFrame?.paused = false
 			this.pauseDate = null
-			this.startDate = Date() // timeFrame?.setDate(Date(), null)
+			this.startDate = Date()
+			this.endDate = null
 			this.breakDuration = 0L
 		}
 	}