Fixed translation for typo in app/code/core/Mage/Core/Model/Observer.php (#2942)

Author: sreichel

app/locale/en_US/Mage_Adminhtml.csv

@@ -104,7 +104,7 @@
 "Already in category","Already in category"
 "Always (during development)","Always (during development)"
 "Amounts","Amounts"
-"An error has occured while syncronizing media storages.","An error has occured while syncronizing media storages."
+"An error has occured while syncronizing media storages.","An error has occurred while syncronizing media storages."
 "An error occurred while adding condition.","An error occurred while adding condition."
 "An error occurred while clearing the JavaScript/CSS cache.","An error occurred while clearing the JavaScript/CSS cache."
 "An error occurred while clearing the configurable swatches image cache.","An error occurred while clearing the configurable swatches image cache."