Add OSGI info to MANIFEST.MF
Eclipse plugins, such as eclipse-wtp-jpa, need it to be exported in the
MANIFEST.MF. This change adds some of this information to that file, by
adding the relevant lines to the pom.xml file, where the manifest is
generated from.
Currently being exported are javax.persistence and javax.persistence.spi.
I don't know if javax.persistence.metamodel or javax.persistence.criteria
should be exported also, but they don't seem to be needed by anything so
I've left them out. javax.persistence.spi isn't necessarily needed either,
but geronimo-jpa exports it, so I just went by that.