Remove accidental dependency from new converters to old

Change-Id: I9cd9e691fb30063a914729d15011f5d50e19d8d4

server/src/main/java/com/vaadin/data/util/converter/AbstractStringToNumberConverter.java

 import java.text.ParsePosition;
 import java.util.Locale;
 
-import com.vaadin.v7.data.util.converter.LegacyConverter.ConversionException;
-
 /**
  * A converter that converts from the number type T to {@link String} and back.
  * Uses the given locale and {@link NumberFormat} for formatting and parsing.
      * @param locale
      *            The locale to use for conversion
      * @return The converted value
-     * @throws ConversionException
-     *             If there was a problem converting the value
      */
-    protected Number convertToNumber(String value, Locale locale)
-            throws ConversionException {
+    protected Number convertToNumber(String value, Locale locale) {
         if (value == null) {
             return null;
         }
         ParsePosition parsePosition = new ParsePosition(0);
         Number parsedValue = getFormat(locale).parse(value, parsePosition);
         if (parsePosition.getIndex() != value.length()) {
-            throw new ConversionException("Could not convert '" + value + "'");
+            throw new IllegalArgumentException(
+                    "Could not convert '" + value + "'");
         }
 
         if (parsedValue == null) {

server/src/main/java/com/vaadin/data/util/converter/Converter.java

 import java.util.function.Function;
 
 import com.vaadin.data.Binder.Binding;
-import com.vaadin.v7.data.util.converter.LegacyConverter.ConversionException;
 import com.vaadin.data.Result;
 
 /**
         return new Converter<P, M>() {
 
             @Override
-            public Result<M> convertToModel(P value, Locale locale)
-                    throws ConversionException {
+            public Result<M> convertToModel(P value, Locale locale) {
                 return toModel.apply(value);
             }
 
             @Override
-            public P convertToPresentation(M value, Locale locale)
-                    throws ConversionException {
+            public P convertToPresentation(M value, Locale locale) {
                 return toPresentation.apply(value);
             }
         };

server/src/main/java/com/vaadin/data/util/converter/StringToIntegerConverter.java

 import java.util.Locale;
 
 import com.vaadin.data.Result;
-import com.vaadin.v7.data.util.converter.LegacyConverter.ConversionException;
 
 /**
  * A converter that converts from {@link String} to {@link Integer} and back.
     }
 
     @Override
-    public Result<Integer> convertToModel(String value, Locale locale)
-            throws ConversionException {
+    public Result<Integer> convertToModel(String value, Locale locale) {
         Number n = convertToNumber(value, locale);
 
         if (n == null) {