Update to atlasexternals 2.0.34

Another attempt at fixing the `flake8` installation adding `mccabe` and
`backports` as explicit RPM dependencies.

Projects/AnalysisBase/externals.txt

@@ -6,4 +6,4 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AnalysisBaseExternalsVersion = 2.0.33
+AnalysisBaseExternalsVersion = 2.0.34

Projects/AnalysisTop/externals.txt

 # Versions of the various externals to build before starting the build of
 # this project, when doing a full stack nightly build.
 
-AnalysisBaseExternalsVersion = 2.0.33
+AnalysisBaseExternalsVersion = 2.0.34

Projects/AthDataQuality/externals.txt

@@ -5,4 +5,4 @@
 # an "origin/" prefix before it. For tags however this is explicitly
 # forbidden.
 
-AtlasExternalsVersion = 2.0.33
+AtlasExternalsVersion = 2.0.34

Projects/AthSimulation/externals.txt

@@ -6,7 +6,7 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AthSimulationExternalsVersion = 2.0.33
+AthSimulationExternalsVersion = 2.0.34
 
 # The version of atlas/Gaudi to use:
 GaudiVersion = v32r0.002

Projects/Athena/externals.txt

@@ -6,7 +6,7 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AthenaExternalsVersion = 2.0.33
+AthenaExternalsVersion = 2.0.34
 
 # The version of atlas/Gaudi to use:
 GaudiVersion = v32r0.002

Projects/VP1Light/externals.txt

@@ -6,4 +6,4 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-VP1LightExternalsVersion = 2.0.33
+VP1LightExternalsVersion = 2.0.34