Typo in unrelated config file can block netconf-connector functionality

The severity of the resulting buggy state may be caused by some other component, but config subsystem should filter out the triggering condition of this bug.

This description uses PCEP as the component with config files unrelated to netconf connector.

Steps to reproduce:
0. Download an unpack a recent Lithium snapshot build with otherwise working netconf connector.
1. start ODL
2. feature:install odl-restconf-noauth odl-bgpcep-pcep-all odl-netconf-connector-all
3. wait few minutes to make sure netconf-connector had time to start
4. curl -s 127.0.0.1:8181/restconf/config/network-topology:network-topology/topology/topology-netconf/node/controller-config/yang-ext:mount/config:modules
5. see all modules configured as intended
6. kill ODL java process
7. rm -rf data/ snapshots/ journal/ lock idmlight.db.mv.db
8. edit etc/opendaylight/karaf/39-pcep-provider.xml value in line 52, from "stateful07" to "stateful06".
9. - 12. repeat steps 1. - 4.
13. see {"errors":{"error":[

{"error-type":"protocol","error-tag":"unknown-element","error-message":"Mount point does not exist."}

]}}

Alternative to step 3: monitor karaf.log till you see netconf-connector success message.
Alternative to step 11: monitor karaf.log, see it stops scrolling forever just after Leader moves node to [Up].

The only interesting log I see buried in such step 11 is this:
2015-05-29 09:50:46,959 | WARN | r - ConfigPusher | FeatureConfigPusher | 132 - config-persister-feature-adapter - 0.3.0.SNAPSHOT | Karaf featuresService.listInstalledFeatures() has not yet finished installing feature (retry 0) odl-bgpcep-pcep-all 0.4.0-SNAPSHOT