discovery: remove duplication for new remote head discovery
#!/bin/shhg init testcd testecho foo > ahg ci -Amahg up -r0000echo bar > aecho % should issue warninghg ci -Ambhg up -r0000echo stuffy > aecho % should not issue warninghg ci -q -Amchg up -r0000echo crap > ahg branch testingecho % should not issue warninghg ci -q -Amd