Make vaadin-shared Import-Package empty as it should be

Change-Id: Icccc655b975558e859b961c4eed0f24fdc86b34c

shared/pom.xml

@@ -117,6 +117,7 @@
 						<Bundle-RequiredExecutionEnvironment>JavaSE-1.6</Bundle-RequiredExecutionEnvironment>
 						<Bundle-Version>${parsedVersion.majorVersion}.${parsedVersion.minorVersion}.${parsedVersion.incrementalVersion}</Bundle-Version>
 						<Export-Package>com.vaadin.*;version="${parsedVersion.majorVersion}.${parsedVersion.minorVersion}.${parsedVersion.incrementalVersion}",elemental.*;version="${parsedVersion.majorVersion}.${parsedVersion.minorVersion}.${parsedVersion.incrementalVersion}"</Export-Package>
+						<Import-Package></Import-Package>
 						<Require-Bundle></Require-Bundle>
 					</instructions>
 				</configuration>