ReplaceRunKeywordIf should remove unnecessary ELSE branch

[bhirsz]

This 'trick' was used to overwrite some variable with keyword value under some condition:

    ${variable}    Run Keyword If    ${something}
    ...    Catenate    ${variable}    sed -i 's/substring/${OTHER}calc/' file.conf ;
    ...    ELSE    Set Variable    ${variable}

While converting it to IF we end up with:

IF    ${something}
    ${variable}    Catenate    ${variable}    sed -i 's/substring/${OTHER}calc/' file.conf ;
ELSE
    ${variable}    Set Variable    ${variable}
END

while it could be just:

IF    ${something}
    ${variable}    Catenate    ${variable}    sed -i 's/substring/${OTHER}calc/' file.conf ;
END