engine: [cleanup] Rename RunQuery to runQuery

Findbugs warning message:
Backend.java:458, NM_METHOD_NAMING_CONVENTION, Priority: Low

The method name
org.ovirt.engine.core.bll.Backend.RunQuery(VdcQueryType,
                                           VdcQueryParametersBase)
doesn't start with a lower case letter

Methods should be verbs, in mixed case with the first letter lowercase,
with the first letter of each internal word capitalized.

Change-Id: Ia339bc402d36fe22e4017a8b891ed64af2e0cef2
Signed-off-by: Adam Litke <alitke@redhat.com>