Allow disabling svn branches/tags, fixes composer/satis#43

doc/05-repositories.md

@@ -259,6 +259,9 @@ repository like this:
         ]
     }
 
+If you have no branches or tags directory you can disable them entirely by
+setting the `branches-path` or `tags-path` to `false`.
+
 ### PEAR
 
 It is possible to install packages from any PEAR channel by using the `pear`

src/Composer/Repository/Vcs/SvnDriver.php

@@ -160,6 +160,7 @@ class SvnDriver extends VcsDriver
         if (null === $this->tags) {
             $this->tags = array();
 
+            if ($this->tagsPath !== false) {
                 $output = $this->execute('svn ls --verbose', $this->baseUrl . '/' . $this->tagsPath);
                 if ($output) {
                     foreach ($this->process->splitLines($output) as $line) {
@@ -173,6 +174,7 @@ class SvnDriver extends VcsDriver
                     }
                 }
             }
+        }
 
         return $this->tags;
     }
@@ -200,6 +202,7 @@ class SvnDriver extends VcsDriver
             }
             unset($output);
 
+            if ($this->branchesPath !== false) {
                 $output = $this->execute('svn ls --verbose', $this->baseUrl . '/' . $this->branchesPath);
                 if ($output) {
                     foreach ($this->process->splitLines(trim($output)) as $line) {
@@ -213,6 +216,7 @@ class SvnDriver extends VcsDriver
                     }
                 }
             }
+        }
 
         return $this->branches;
     }