Change http to https, make installation of glog, gflags and double-conversion consistent; use github url for double-conversion

Summary:
To fix the error:

sudo: apt-get: command not found
fetching glog from svn (apt-get fails)
svn: E175002: Unable to connect to a repository at URL 'http://google-glog.googlecode.com/svn/trunk'
svn: E175002: OPTIONS of 'http://google-glog.googlecode.com/svn/trunk': Could not read status line: connection was closed by server (http://google-glog.googlecode.com)
Closes #23
Github Author: NagaChaitanya Vellanki <me@chaitanyavellanki.com>

{sync, type="child", parent="github", parentrepo="facebook/proxygen", parentprnum="23", parentprfbid="567899116687621"}

Test Plan: Imported from GitHub, without a `Test Plan:` line.

Reviewed By: woo@fb.com

Subscribers: bmatheny

FB internal diff: D1712402

Signature: t1:1712402:1417720645:519ebd9aaea051b0ad529752f1b8b6cea546ab5d

Author: Viswanath Sivakumar

proxygen/deps.sh

@@ -32,9 +32,9 @@ sudo apt-get install -yq \
 # deps.sh in fbthrift and folly builds anyways (no trap there)
 if ! sudo apt-get install libgoogle-glog-dev; 
 then
-	echo "fetching glog from svn (apt-get fails)"
 	if [ ! -e google-glog ]; then
-		svn checkout http://google-glog.googlecode.com/svn/trunk/ google-glog
+    echo "fetching glog from svn (apt-get failed)"
+		svn checkout https://google-glog.googlecode.com/svn/trunk/ google-glog
 		cd google-glog
 		./configure
 		make
@@ -43,25 +43,24 @@ then
 	fi
 fi
 
-if ! sudo apt-get install libgflags-dev; 
+if ! sudo apt-get install libgflags-dev;
 then
 	if [ ! -e google-gflags ]; then
-		echo "Fetching and building libgflags"
-		wget https://github.com/schuhschuh/gflags/archive/v2.0.tar.gz
-		mkdir google-gflags
-		tar xf v2.0.tar.gz -C google-gflags
-		cd google-gflags/gflags-2.0/
-		./configure
-		make
-		sudo make install
-		cd ../../
+    echo "Fetching gflags from svn (apt-get failed)"
+    svn checkout https://google-gflags.googlecode.com/svn/trunk/ google-gflags
+    cd google-gflags
+    ./configure
+    make
+    sudo make install
+    cd ..
 	fi
 fi
 
-if  ! sudo apt-get install libdouble-conversion-dev; 
+if  ! sudo apt-get install libdouble-conversion-dev;
 then
 	if [ ! -e double-conversion ]; then
-		git clone https://code.google.com/p/double-conversion double-conversion
+    echo "Fetching double-conversion from git (apt-get failed)"
+		git clone https://github.com/floitsch/double-conversion.git double-conversion
 		cd double-conversion
 		cmake . -DBUILD_SHARED_LIBS=ON
 		sudo make install