Remove OmeroJava/src from top-level .classpath-template

After @bpindelski's recent changes to tools/OmeroJava,
there is no longer any source under OmeroJava, but build-eclipse
produced a .classpath file which referenced it leaving the workspace
broken.

Re-running `./build.py build-dev` with this change should produce
a new working Eclipse classpath file.
Merge pull request #1470 from joshmoore/eclipse-OmeroJava-src

Eclipse OmeroJava src