Fixes #3210: improve debug log when there is an error in Technique
Merge pull request #24 from VinceMacBuche/bug_3210/log_Technique_error

Fixes #3210: improve debug log when there is an error in Technique
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7
Merge branch 'branches/rudder/2.7'