Source control management (SCM) support is a feature SQL Developer picks up from its base JDeveloper version. According to Bug 13388184 - ORG.TIGRIS.SUBVERSION.SVNCLIENTADAPTER.SVNCLIENTEXCEPTION IN O.JI.VCS.SVN.SVNUR Bug 14528868 - ORG.TIGRIS.SUBVERSION.SVNCLIENTADAPTER.SVNCLIENTEXCEPTION IN O.JI.VCS.SVN.SVNUR
logged against JDeveloper 12.1.2 and 11.1.2, neither of which is the current base for SQL Developer, but only prospective future base versions ...
Subversion 1.7 is not supported, don't upgrade you SVNKit of JDeveloper
... and ...
JDeveloper does not support Subversion Working Copy format 1.7.
You will need to checkout using JDeveloper not using a Subversion 1.7 client
It is against Oracle policy to comment on potential future features / release dates. That said, the scenario SVN / SQL Developer users are probably hoping for is:
1. Some future JDeveloper release has committed to the requirement of supporting SVN KIT 1.7.x.
2. Some future SQL Developer release has committed to re-basing on that JDeveloper release.
It is reasonable to assume both (1) and (2) will happen, but I have no idea when. We just put out 3.2.2 on October 31st. JDeveloper 220.127.116.11.0 came out in September. Looking at JDeveloper's release history,
that pattern makes it highly unlikely any new non-maintenance JDeveloper production release could come out prior to Q3 2013, at the earliest. So my guess is you still have quite a wait ahead of you.