Revert "added gradle clean to build.sh to ensure everything is up to date"

This reverts commit bf7018ec.

openbis_all/source/bash/build/build.sh

@@ -37,12 +37,12 @@ if [ $? -ne 0 ]; then echo "Tag does not exist!"; exit 1; fi
 
 # build
 cd openbis_standard_technologies
-./gradlew :clean :clientsAndApis -x test
-./gradlew :clean :generateJavadoc
+./gradlew :clientsAndApis -x test
+./gradlew :generateJavadoc
 cd ../installation
-./gradlew :clean :build -x test
+./gradlew :build -x test
 cd ../plasmid
-./gradlew :clean :build -x test
+./gradlew :build -x test
 
 cd ../..