Existence of directory is not checked when saving corpus properties
By default ANNIS (service) saves corpus properties in the directory `.annis/data` under the user's home directory. It does not ensure that the directory exists, nor do the installation instructions for public servers give any suggestion to create it. So the first time a user attempts to import a corpus, a `FileNotFoundException` is raised and the corpus.properties file is not saved. The fix is trivial.

diff --git a/annis-service/src/main/java/annis/dao/SpringAnnisDao.java b/annis-service/src/main/java/annis/dao/SpringAnnisDao.java
index 7841746c1..99005e534 100644
--- a/annis-service/src/main/java/annis/dao/SpringAnnisDao.java
+++ b/annis-service/src/main/java/annis/dao/SpringAnnisDao.java
@@ -336,6 +336,17 @@ public class SpringAnnisDao extends SimpleJdbcDaoSupport implements AnnisDao,
 
 
     File dir = getRealDataDir();
+    if (!dir.exists())
+    {
+      if (dir.mkdirs())
+      {
+        log.info("Created directory " + dir);
+      }
+      else
+      {
+        log.error("Directory " + dir + " doesn't exist and cannot be created");
+      }
+    }
 
     if (fileName == null)
     {
['annis-service/src/main/java/annis/dao/SpringAnnisDao.java']