KeyUtil: Remove unused setEncoderImpl method
KeyUtil: Remove unused setEncoderImpl method

References to com.google.gwtorm.server.SchemaFactory in the method
javadoc cause warnings in Eclipse because SchemaFactory does not
exist any more.

There are no callers of setEncoderImpl in the core Gerrit code, so
we can just remove it.

Change-Id: I1c13ff77ae659d3cd9671b99c5f703bebb8dac37

qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit