ICU-7287 We shipped v20100408 plug-ins to Ecslipe team, but they found that plugin.properties is missed in the source plugin.  I found that the problem was caused by a regression problem in Eclipse 3.6M6 that was used for building v20100408.  We agreed to rebuild ICU4J plug-in with Eclipse 3.6M5.  For this reason, I need to update the plug-in version string.

X-SVN-Rev: 27929
diff --git a/build.properties b/build.properties
index 6d6c4f2..daf5ba8 100644
--- a/build.properties
+++ b/build.properties
@@ -29,4 +29,4 @@
 icu4j.plugin.impl.version.string=4.2.1
 copyright.eclipse=Licensed Materials - Property of IBM \n (C) Copyright IBM Corp. 2000, 2010. All Rights Reserved. \n IBM is a registered trademark of IBM Corp.
 
-icu4j.eclipse.build.version.string=4.2.1.v20100408
+icu4j.eclipse.build.version.string=4.2.1.v20100412