kernel_build.sh: Improve branch name sanitization

Extended sed pattern to replace some more characters
which could be in a branch name

Signed-off-by: Shreeya Patel <[email protected]>

Author: shreeya-patel98

kernel_build.sh

@@ -7,7 +7,7 @@ fi
 
 pwd
 
-BRANCH=$(git branch | grep \* | cut -d ' ' -f2 | sed -r 's/[{}/]/_/g')
+BRANCH=$(git branch | grep \* | cut -d ' ' -f2 | sed 's/[{}()]//g; s/\//_/g')
 
 START=$(date +%s)
 START_MRPROPER=$(date +%s)