Don't double (or triple) up common error messages

process_common_errors() was called thrice, each time appending to the
existing error message, and leading to confusing repetition in the
message that was finally displayed.

Fixes #7498
Relax suds module requirement
Merge branch 'evgkrsk-suds' into devel
Merge module_vars into inject during template instead of updating

This way we won't overwrite values that are stored in the inject
with module_vars that should be lower precedence.

Fixes #7510
Merge pull request #7517 from amenonsen/double-error

Don't double (or triple) up common error messages
Replace CommandException with Exception
Merge pull request #7524 from aresch/patch-2

Replace CommandException with Exception
Fix typo in variable name
Merge pull request #7526 from aresch/patch-3

Fix typo in variable name