Android: Make lineHeight accept decimal values

Summary:
Make android-version accept a decimal
number as lineHeight.

Credits where due, solution was given in this
issue: facebook/react-native#10607

According to the w3 spec the property
line-height should accept decimal values
(and it does on iOS) but the android
version has the wrong data-type for the
shadowed method, resulting in a stacktrace
saying:
com.facebook.react.bridge.UnexpectedNativeTypeException: TypeError:
expected dynamic type `int64', but had type `double'

Setting it to a float makes it accept
decmial values as it should.

* Create an app without this commit and create the same app with this commit:
In both apps:
- Leave line-height undefined. Behavior is unaffected by this commit.
- Set lineHeight to a integer number. Behavior is unaffected by this commit.
- Set lineHeight to a decimal number. Line height is now rendered with decimals in the app with this fix.

* Run android integration tests to see nothing
  else broke.

Sign the [CLA][2], if you haven't already.

Small pull requests are much easier to review and more likely to get merged. Make sure the PR does only one thing, otherwise please split it.

Make sure all **tests pass** on both [Travis][3] and [Circle CI][4]. PRs that break tests are unlikely to be merged.

For more info, see the ["Pull Requests"][5] section of our "Contributing" guidelines.

[1]: https://medium.com/martinkonicek/what-is-a-test-plan-8bfc840ec171#.y9lcuqqi9
[2]: https://code.facebook.com/cla
[3]: https://travis-ci.org/facebook/react-native
[4]: http://circleci.com/gh/facebook/react-native
[5]: https://github.com/facebook/react-native/blob/master/CONTRIBUTING.md#pull-requests
Closes https://github.com/facebook/react-native/pull/13843

Differential Revision: D5152982

Pulled By: shergin

fbshipit-source-id: cda3b72497a6c27d6948b31ec846640a8913775a

ReactAndroid/src/main/java/com/facebook/react/views/text/ReactTextShadowNode.java

@@ -339,7 +339,7 @@ public class ReactTextShadowNode extends LayoutShadowNode {
   protected int mNumberOfLines = UNSET;
   protected int mFontSize = UNSET;
   protected float mFontSizeInput = UNSET;
-  protected int mLineHeightInput = UNSET;
+  protected float mLineHeightInput = UNSET;
   protected int mTextAlign = Gravity.NO_GRAVITY;
   protected int mTextBreakStrategy = (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) ?
       0 : Layout.BREAK_STRATEGY_HIGH_QUALITY;
@@ -441,8 +441,8 @@ public class ReactTextShadowNode extends LayoutShadowNode {
     markUpdated();
   }
 
-  @ReactProp(name = ViewProps.LINE_HEIGHT, defaultInt = UNSET)
-  public void setLineHeight(int lineHeight) {
+  @ReactProp(name = ViewProps.LINE_HEIGHT, defaultFloat = UNSET)
+  public void setLineHeight(float lineHeight) {
     mLineHeightInput = lineHeight;
     if (lineHeight == UNSET) {
       mLineHeight = Float.NaN;