For bug 379241, bump automation config for RC3

tools/release/configs/fx-moz18-bootstrap.cfg

@@ -7,7 +7,7 @@ branchTag       = MOZILLA_1_8_BRANCH
 # GECKO181_20070501_RELBRANCH created manually from this pull date
 pullDate        = 2007-05-01 01:30 PDT
 l10n_pullDate   = 
-rc              = 2
+rc              = 3
 # oldVersion and oldRc refer to the previous release
 oldVersion      = 2.0.0.3
 oldRc           = 1