Sonar clean-up: braces for control statements

Sonar clean-up: braces for control statements

Add braces for if, while, for statements. (Automated, thanks IntelliJ!)

In a few cases a different change was more appropriate:
* ConfigurationServiceImpl.java: in unsetOvsdbConfigurationService(),
  the if is redundant, we might as well set to null unconditionnally.
* ConnectionServiceImpl.java: likewise
* OvsdbLibraryIt.java: instead of
  if (...) { return true; } return false;
  just
  return ...;
* OvsdbVswitchdSchemaConstants.java: likewise

Change-Id: Ib35b395a64c3caa17c32a3f51c763d8a2f88b093
Signed-off-by: Stephen Kitt <skitt@redhat.com>