Update Jenkinsfile

Author: miklis

Jenkinsfile

@@ -57,7 +57,7 @@ def morpheusBuildStep(target, compilerLabel, toolchain) {
       deleteDir()
       dir("mbed-os") {
         checkout scm
-        execute ("git log -1 --no-merges --pretty=format:'%H'" > GIT_REVISION)
+        execute ("git log -1 --no-merges --pretty=format:'%H' > GIT_REVISION")
         env.GIT_REVISION = readFile ("GIT_REVISION")
         execute ("mbed deploy --protocol ssh")
         execute ("mbed test --compile -m ${target} -t ${toolchain} -c")