common.sh: Rewrite of proxy information checks using test(1)

Signed-off-by: Erik Alexandre Pucci <eap08@c3sl.ufpr.br>
Signed-off-by: Danilo K. S. Yorinori <danilok@c3sl.ufpr.br>

common.sh

@@ -36,18 +36,10 @@ function getProxyConf()
     puid=$(grep "^puid=" ${PROXYCONF} | cut -f2 -d=)
     ppasswd=$(grep "^ppasswd=" ${PROXYCONF} | cut -f2 -d=)
 
-    if test -n "${phost}"; then
-        phost="--phost=${phost}"
-    fi
-    if test -n "${pport}"; then
-        pport="--pport=${pport}"
-    fi
-    if test -n "${puid}"; then
-        puid="--puid=${puid}"
-    fi
-    if test -n "${ppasswd}"; then
-        ppasswd="--ppasswd=${ppasswd}"
-    fi
+    test -n "${phost}" && phost="--phost=${phost}"
+    test -n "${pport}" && pport="--pport=${pport}"
+    test -n "${puid}" && puid="--puid=${puid}"
+    test -n "${ppasswd}" && ppasswd="--ppasswd=${ppasswd}"
 }
 
 function tryWget(){