Fixed SCons build when not running from the V8 root directory.

TBR=ager@chromium.org
Review URL: http://codereview.chromium.org/100201

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1827 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

SConstruct

@@ -613,7 +613,7 @@ def GetVersionComponents():
               BUILD_NUMBER_PATTERN,
               PATCH_LEVEL_PATTERN]
 
-  source = open(join('src', 'version.cc')).read()
+  source = open(join(root_dir, 'src', 'version.cc')).read()
   version_components = []
   for pattern in patterns:
     match = pattern.search(source)
@@ -636,7 +636,7 @@ def GetVersion():
 def GetSpecificSONAME():
   SONAME_PATTERN = re.compile(r"#define\s+SONAME\s+\"(.*)\"")
   
-  source = open(join('src', 'version.cc')).read()
+  source = open(join(root_dir, 'src', 'version.cc')).read()
   match = SONAME_PATTERN.search(source)
   
   if match: