Updating file name to avoid error

Change-Id: Id1e150e9f715c258f853d1cf88a1be72246b503d
Signed-off-by: Harman Singh <harmasin@cisco.com>

diff --git a/main/archetypes/archetype-md-sal-app-simple/src/main/resources/archetype-resources/generate/src/main/template/provider/yang-gen-sal/ProviderImpl.vm b/main/archetypes/archetype-md-sal-app-simple/src/main/resources/archetype-resources/generate/src/main/template/provider/yang-gen-sal/providerImpl.vm
similarity index 100%
rename from main/archetypes/archetype-md-sal-app-simple/src/main/resources/archetype-resources/generate/src/main/template/provider/yang-gen-sal/ProviderImpl.vm
rename to main/archetypes/archetype-md-sal-app-simple/src/main/resources/archetype-resources/generate/src/main/template/provider/yang-gen-sal/providerImpl.vm